parablast 
parablast (par'a-blast). ii. [< Gr. vapa, beside, 
+ ,3/.aoTof, germ.] 1. The supplementary or 
nutritive yolk of a meroblastic egg or metovum, 
as distinguished from the archiblast, or forma- 
tive yolk. Willielm His. 2. Same as metso- 
blast. Microscop. Sci., XXIX. 195. 
Sections of the eggs of Trachinns vipara at this stage 
show that the parablast of Klein, the intermediate layer 
of American authors, is made up of a large number of 
free cells, and nuclei are absorbed from the yolk, which 
contribute to a very great extent to build up the hypo- 
blast. Science, IV. 341. 
parablastic (par-a-blas'tik), a. [< parablast + 
-iV.] Of or pertaining to the parablast; de- 
rived from the parablast. 
parable 1 (par'a-bl), . [< ME. parable, para- 
bole, < OF. parable, parabole, F. parabole = Sp. 
parabola = Pg. It. parabola, < L. parabola, 
parabole, a comparison, LL. parabola, eccl., an 
allegorical relation, a parable, proverb, taunt- 
ing speech, any speech, ML. also a word, < Gr. 
napafiokri, a comparison, < 7tapa(ld?.faiv, < irapd, 
beside, + pdtAeiv, throw. Hence also (from L. 
parabola) E. parole, part, parley, palaver, etc. 
Cf. parabola*.] 1. A comparison; similitude. 
Been ther none othere resemblances 
That ye may likne youre parables unto 
But if a sely wyf be oon of tho ? 
Chaucer, Wife of Bath's Tale, 1. 369. 
Specifically 2. An allegorical relation or rep- 
resentation from which a moral is drawn for 
instruction ; an apologue. It is a species of fable, 
and differs from the apologue in that it deals with events 
which, though fictitious, might reasonably have happened 
in nature. The word is also employed in the English Bible 
to signify a proverb, a proverbial or notable saying, a thing 
darkly or figuratively expressed. 
I will open my mouth in a parable ; I will utter dark 
sayings of old. Fs. Ixxviii. 2. 
Shall not all these take up a parable against him, and a 
taunting proverb against him? Hab. ii 6. 
Thou shalt never get such a secret from me but by a 
parable. Shale., T. G. of V., ii. 6. 41. 
= Syn. Metaphor, Companion, etc. (seesimite); fable, etc. 
(see myth). 
parable 1 (par'a-bl), v. t.; pret. and pp. para- 
bled, ppr. parabling. [< parable^, n.~\ To rep- 
resent by a parable or allegorical representa- 
tion. 
That was chiefly meant which by the ancient sages was 
thus parabled. Milton, Divorce, i. 8. 
parable' 2 t (par'a-bl), n. [< L. parabilis, easily 
procured,< parare, prepare : see pare 1 .] Capa- 
ble of being procured, prepared, or provided. 
What course shall he take, being now capable and ready? 
The most parable and easy, and about which many are 
employed, is to teach a school. 
Burton, Anat. of Mel., p. 190. 
They were not well-wishers unto parable physic, or rem- 
edies easily acquired, who derived medicines from the 
phoenix. Sir T. Browne, Vulg. Err., ill. 12. 
parablepsis (par-a-blep'sis), n. [NL., < Gr. 
wapd, beside, + /3/Ui/c, vision, < ftt-eneiv, see.] 
False vision. 
parablepsy (par'a-blep-si), n. [< NL. para- 
blepsis, q. v.] Parablepsis. 
parabola 1 (pa-rab'o-la), n. Same as parabole. 
Whensoeuer by your similitudeye will seeme to teach any 
moralitie or good lesson by speeches misticall and darke, 
or farre fette, vnder a sence metaphoricall applying one 
natural! thing to another, or one case to another, inferring 
by them a like consequence in other cases, the Greekes call 
it Parabola. Puttenham, Arte of Eng. Poesie, p. 206. 
parabola 2 (pa-rab'o-la), n. [= F. parabole = 
Sp. parabola Pg. ft. parabola, < NL. para- 
bola, a parabola, < Gr. Ttapafloliii, a parabola 
(see def.), so called by Apollonius of Perga, 
lit. ' superposition,' < irapa.pah.teiv, throw beside, 
compare: see parable*-.] 1. A curve commonly 
defined as the intersection of a cone with a 
plane parallel with its side. The name is derived 
from the following property. Let the figure represent the 
cone. Let ABG be the triangle 
through the axis of the cone. 
Let DE be a line perpendicular 
to this triangle, cutting BG in 
H. Let the cone be cut by a 
plane through DE parallel to 
AG, so that the intersection 
with the cone will be the curve 
called the parabola. Let Z be 
the point wnere this curve cuts 
AB. Then the line ZH is called 
by Apollonius the diameter of 
the parabola, or the principal 
diameter, or the diameter from 
generation; it is now called 
the axis. From Z draw ZT at 
right angles to ZH and in the plane of ZH and AB, of 
such a length as to make ZT:ZA::BG2: AB.AG. This 
line ZT is called the latus rectum ; it is now also called the 
parameter. Now take any point whatever, as K, on the 
curve. From it draw KL parallel to DE, meeting the diam- 
eter in L. ZL is called the abscissa. If now, on ZL as a base, 
we erect a rectangle equal in area to the square on KL, the 
other side of this rectangle may be precisely superposed 
Parabola, as formed from 
cone. 
4272 
upon the latus rectum, ZT. This property constitutes the 
best practical definition of the parabola. If a similar con- 
struction were made in the case of the ellipse, the side of 
the rectangle would fall short of the latus rectum ; in the 
case of the hyperbola, would surpass it. The modern scien- 
tific definition of the parabola is that it is 
that plane curve of the second order which 
is tangent to the line at infinity. The parab- 
ola is also frequently denned as the curve 
which is everywhere equally distant from 
a fixed point called its focus, and from a 
fixed line called its directrix. The normal 
to a parabola at every point on the curve ?,''""S h ,J 
bisects the angle between the line parallel "'"" ",[' ; 
to the axis and the line to the focus. See rectrix AB. 
also cuts under conic. 
2. By extension, any algebraical curve, or 
branch of a curve, having the line at infinity 
as a real tangent. Such a curve runs off to infinity 
without approximating to an asymptote. If the branch 
has an asymptote at one end but not at the other, it is not 
commonly termed a parabola. Bell-shaped, biquad- 
ratic parabola. See the adjectives. Campanfform 
parabola, a cubic divergent parabola without node or 
cusp. Cartesian parabola, a plane cubic curve hav- 
ing the line at infinity a tangent at its crunode. See tri- 
dent. Cubical or cubic parabola, a parab- 
ola of the third order that is, such that 
every line in the plane meets it in three 
points, one at least real, though it may be at 
infinity: especially, the curve better described 
as the central cubital parabola, which has a 
cusp on the line at infinity, and the normal at 
its inflection passing through the cusp. There 
is also a non-plane curve so called. Cuspidate parab- 
ola, a parabola having a cusp. Divergent parabola, 
a plane curve having the line at infinity as an inflectional 
tangent. Double parabola, a plane curve of the third 
class, having the line at infinity for a double tangent. 
Helicoid parabola. See helicoid. Neilian parabola, 
the semicubical parabola, which was rectified, before any 
other curve, by Wm. Neil in 1657. Nodate parabola, 
a parabola having a crunode. Oval parabola, a parab- 
ola having an oval. Plane 
cubic parabola. seecuWc. 
Punctate parabola, a 
parabola having an acnode. 
Semicubical parabola, 
the cuspidal cubical parabo- 
la, Otherwise called the Neil- Neil's Semicubical Parabola. 
ian parabola. 
parabolanus (par"a-bo-la'nus), n. ; pi. parabo- 
lani (-ni). [LL., (. parabolas, a reckless fel- 
low who risks his life at anything, < Gr. ira- 
pdfioljif, venturesome, reckless, < vapafidMeiv, 
throw beside: see parable^.] In the Christian 
Church in the East, during the third, fourth, 
and fifth centuries, one of a class of lay assis- 
tants to the clergy, whose especial function was 
nursing the sick. The name is generally ascribed to 
the fact of their reckless bravery in nursing patients suf- 
fering from infectious diseases. 
Introduce him to the parabolani. 
Kingdey, Hypatia, iv. 
parabole (pa-rab'o-le), n. [L., also parabola, 
a comparison: see parable^.] In rhet., a com- 
parison ; specifically, a simile, especially a for- 
mal simile, as in poetry or poetic prose, taken 
from a present or imagined object or event: 
distinguished from a paradigm, or comparison 
with a real past event. 
parabolic 1 (par-a-bol'ik), a. [= F. parabolique 
= Sp. parabdlico = Pg. It. parabolico, < LGr. 
7rapa/3o7uK6f, figurative, < Gr. irapa/iohq, a com- 
parison, parable : see parabola^, parabola, par- 
ablel.] 1. Of or pertaining to a parable; of 
the nature of a parable. 2. Of or pertaining 
to parabole ; of the nature of parabole. 
Creation mark the word transcends all experience, 
transcends even conception itself. Hence the words de- 
scribing Creation must, in the very nature of the case, be 
figurative or parabolic. 
0. D. Boardman, Creative Week, p. 20. 
parabolic' 2 (par-a-bol'ik), a. [= F. para- 
bolique = Sp. parabolico = Pg. It. parabolico, 
< NL. parabolicus, < parabola, a parabola: see 
parabola^.] 1. Having the form or outline of 
a parabola ; of, pertaining to, or resembling a 
parabola. 2. Having only one point at infini- 
ty, or otherwise determined in character by the 
coalescence of two quantities Parabolic co- 
noid. See conoid, 1. Parabolic curve, a curve whose 
equation is of the form 
y = a + bx + K& + dx3 + ex* + etc. 
Parabolic cylinder, a surface generated by a line mov- 
ing parallel to itself so that every point of it describes 
a parabola : this is the only surface whose plane sections 
are all parabolas. Parabolic epicycloid, geometry, 
illuminator, logarithm. See the nouns. Parabolic 
mirror. See mirror, 2. Parabolic point, a point on 
a surface whose indicatrix is composed of two parallel 
straight lines : it is a cusp on the section of the surface 
made by the tangent-plane. Parabolic pyramldold, 
a solid differing from a pyramid in that the edges that 
meet in the vertex instead of being straight lines are 
parabolas. Parabolic space, (a) An area bounded by 
a parabola and a straight line, (b) A space in which the 
sum of the three angles of every triangle is equal to two 
right angles : so called because the two points at infinity 
on every straight line In such space coincide ; also, every 
point in every plane in such a space is a point of no cur- 
vature, and is therefore a parabolic point. Parabolic 
parachordal 
spindle, a solid generated by the rotation of the part of 
a parabola cut off by a double ordinate about such ordi- 
nate. Parabolic spiral, a curve of the equation r? = p. 
parabolical (par-a-bol'i-kal), a. [< parabolic* 
+ -/.] Same as parabolic^. 
Allusive or parabolical [poesy] is a narration applied 
only to express some special purpose or conceit. 
Bacon, Advancement of Learning, ii. 143. 
parabolically 1 (par-a-bol'i-kal-i), adr. In the 
manner of a parable or of parabole ; by parable 
or by parabole. 
Which words, notwithstanding parabolically intended, 
admit no literal inference. 
Sir T. Brown*, Vulg. Err., vii. 1. 
parabolically 12 (par-a-bol'i-kal-i), adr. In the 
manner or form of a parabola. 
paraboliform (par-a-bol'i-form), a. [= Pg. 
paraboliforme, < NL. parabola, a parabola, + L. 
forma, form.] Tangent to the line at infin- 
ity. 
parabolismt, The operation of dividing an 
algebraic equation by the coefficient of the term 
of the highest degree in the unknown. 
parabolist (pa-rab'o-list), n. [< L. parabola, a 
parable, + -itst.] A writer or narrator of para- 
bles. Boothroyd. 
paraboloid (pa-rab'o-loid), n. [= F. paraboloids 
= Pg. It.paraboloide, < Gr. KapaftoM/, a parabola, 
+ fMof, form.] 1. The solid generated by the 
revolution of a parabola about its axis ; a para- 
bolic conoid. 2. A curve whose equation is of 
the form axn = y. 
paraboloidal (pa-rab-o-loi'dal), a. [< parabo- 
loid + -al.~] . Pertaining to or resembling a pa- 
raboloid. 
parabranchia (par-a-brang'ki-a), n. ; pi. para- 
branchise (-e). [NL., < Gr. irapd, beside, + fipay- 
Xta, gills.] The so-called second gill or sup- 
plementary branchia of gastropodous mollusks, 
as thedzygobranehia; a modified olfactory tract, 
or osphradium. Encyc. Brit., XVI. 648. 
parabranchial (par-a-brang'ki-al), a. 
branchia + -al.] 
branchise. 
, . 
Of or pertaining to para- 
parabranchiate (par-a-brang'ki-at), a. 
branchia + -ate 1 .] Provided with a para- 
branchia. 
paracarpiumt (par-a-kar'pi-um), n. [NL., < 
Gr. irapa, beside, + 'icaprefa, fruit.] In bot., an 
abortive pistil or ovary. 
Paracelsian (par-a-sel'si-an), a. and n. [< Par- 
acelsux (see def.) "+ -ian"'] I. a. Relating to 
Paracelsus, a Swiss physician, chemist, and 
philosopher (1493-1541), or according with his 
speculations in philosophy or his practice of 
medicine, particularly the latter. He placed stress 
on observation and experiment, and was noted in the de- 
velopment of pharmaceutical chemistry. His philosophi- 
cal views were visionary and theosophlc. 
H. n. One who believed in or practised the 
views or doctrines of Paracelsus ; especially, a 
medical practitioner of his school. Paracel- 
sians were numerous in the sixteenth and sev- 
enteenth centuries. 
Paracelsist (par-a-sel'sist), . [< Paracelsus 
(see Paracelsian)' '+ -ist.~) Same as Paracel- 
sian. 
paracentesis (par'a-sen-te'sis), n. [L., < Gr. 
irapcudvriiaif, < TrapaKevrelv, tap, < irapd, beside, -f 
Kcvrflv, pierce: see center 1 .] In surg., the per- 
foration of a cavity of the body with a trocar 
or other suitable instrument, for the evacua- 
tion of any effused fluid ; the operation of tap- 
ping, as for hydrothorax or ascites. Different 
forms of the operation are specified byname, as 
cardiocentesis, paracentesis thoracis, paracentesis 
abdominis, etc. 
paracentral (par-a-sen'tral), a. [< Gr. irapa, 
beside, + Kkvrpov, .center: see central.] In mint.. 
situated alongside or next to a center, cen- 
trum, or central part : specifically applied to a 
fissure and a gyms of the cerebrum alongside 
the central or Rolandic fissure Paracentral 
lobule. See lobule. Paracentral sulcus or fissure, 
a slight furrow running up from the callosomarginal sul- 
CUB, marking off the paracentral lobule in front 
paracentric (par-a-sen'trik), a. [= Sp. para- 
cfatrico = Pg. It."paraeentrieo, < Gr. napd, be- 
side, + Kfvrpav, center: see centric.'] Approach- 
ing to or departing from the center __ Para- 
centric motion. See motion. 
paracentrical (par-a-sen'tri-kal), a. [< para- 
centric + -a?.] Same as paracentric. 
parachordal (par-a-k6r'dal), a. and . [< Gr. 
Trapd, beside, + xop&ri, a cord: see ehordal.] I. 
a. In embryol., lying alongside of the cephalo- 
chord or cranial part of the notochord: spe- 
cifically noting the primitive undifferentiated 
plate of cartilage, or cartilaginous basis eranii, 
