acontium 
Isthmian, and other games. 2. jil. In ..,., 
convoluted cords formed in the Actinia mid 
furnished with tliread-cells. I'<W<H: 
acopt (a-kop'), prr/i. phr. as adv. [<<j3, on, + 
cop 1 , top.] At the top. 
She \\vares a hood, but it stands arop. 
B. Joiuon, Alchemist, ii. Ii. 
Acopa (a-ko'pii), n. pi. [NL., <Gr. ii- priv. + 
A-UJTV/, a handle, the handle of an oar, an oar.] 
1. A prime division of the Tunieata or Axridiii, 
in which the ascidians proper are distinguished 
collectively from the Copelata or Apix-iidiciiln- 
ria. See extract. Compare cuts under Am-i/li/i 
and Appendicularia. 
These two classes were formerly separated according to 
whether they had or had not a propelling tail, as the 
names of the classes showed. I have retained the nomen- 
clature without giving an importance to this character 
which does not belong to it; the larva; of many Acopa 
have the directive organ. A much greater difference be- 
tween the two divisions is to be found in the characters 
of their spiracles. In the Copelata these open on to the 
exterior. In the Acopa. they open into a cavity, which is 
formed from a part of the rudimentary spiracle of the 
Copelata. Qtgenbamr, Corny. Anat. (trans.), p. 889. 
2. [*((/.] A genus of lepidopterous insects. 
acopic (a-kop'ik), a. [< Gr. a/tmrof, removing 
weariness, <a- priv. + KOTOC, weariness, toil, 
orig. a striking, < nm-r-etv, strike.] In med., 
fitted to relieve weariness ; restorative. Bu- 
chanan, Diet. Sci. 
acor (a'kor), n. [L., a sour taste, < acere, be 
sour: see acid.] Acidity, as of the stomach. 
acorn (a'korn, often a'kern), n. [Early mod. E. 
acorn, akorn, eykorn, acron, acquorn, akecorne, 
oakern, okecorn, okehorne, etc.,< late ME. acorn, 
akorn, accorne, acorun, ocorn, occorn, okecorne, 
ackerne, akern, hakern, assibilated achorne, ach- 
arne, atcherne, etc. The reg. mod. form would 
be * akern, in ME. akern (assibilated atcherne, im- 
prop. aspirated hakern), the other forms being 
due to the erroneous notion that the word is a 
derivative of oak, or a compound of oak (ME. 
ook, ok, oc, earlier ac, < AS. ac) and corn (ME. 
and AS. corn), or horn (ME. and AS. horn). A 
similar error has affected the spelling of the 
word in other languages. ME. akern, < AS. 
cecern, tecirn, an acorn, orig. any fruit of the 
field, being prop, an adj. formed (like silvern 
from silver) < aicer, a field, acre (see acre), + 
-n (see -eift) ; = D. alcer, an acorn, < akker, a 
field (but now usually eikel, an acorn, < eik. an 
oak) ; = LG. ekker, an acorn, < akker, a field 
(also ek, au acorn, < eke, an oak) ; = G. ecker (after 
LG.), an acorn, < acker, a field (also eichel, an 
acorn, < eiche, an oak) ; = Icel. akarn, an acorn, 
< akr, a field (not from eik, an oak) ; = Norw. 
aakoni (also aakonn, aakodn, andakall),<aake>; 
a field (not from eik, an oak) ; cf. Sw. ekollon, an 
acorn, < ek, oak, + ollon, an acorn ; = Dan. agern, 
an acorn, < ager, a field (not from eg, an oak) ; 
= Goth. akran, fruit in general, < dkrs, a field. 
Thus acorn has nothing to do with either oak or 
corn.] 1. The fruit of the oak; a one-celled, 
one-seeded, coriaceous, rounded or elongated 
nut, the base of which is surrounded by an in- 
durated scaly cup. Acorns have been used for food 
and are still eaten in various countries. The sweet acorn 
s the fruit of the Quercus Ballota of northwestern Africa 
and is quite palatable, as are also several American species' 
All are excellent food for swine. 
51 
Thei weren wont lyghtly to slaken hir hunger at euene 
nth acornes of okes. Chaucer, Boethius, ii. meter 6. 
Besides the gall which is his proper fruite, hee shootes 
out nakfrns, i. e., ut nunc vocamus acornes and oakes ap- 
ples and polypody and moss. 
Sir T. Browne, Works, I. 203 (ed. Bohn). 
2. Naut., a small ornamental piece of wood, of 
a conical or globular shape, sometimes fixed 
on the point of the spindle above the vane, on 
a masthead, to keep the vane from being 
blown off. 3. Any similar ornamental tip. 
4. Same as acorn-shell, 2. 
Acorn-moth (Holcoccra glanduUlla, Kilcy). 
a larva within acorn; , acorn infested with the larval <-, head 
and thoracic scpnents of larva ; rf. one of the abdominal seimentsof 
larva lateral y.ew ; ,. one of the abdominal segments of larva, dorsal 
in the T h CrOSS S natuml size) ! Z< basal Jointof antenna 
acorn-cup (a'k6rn-kup), . The hardened in- 
volucre covering the base of an acorn, The 
acorn-cups of the IJurrfnx ./>i7,,/,.,, under the nulne m- 
luiiiii, have become au important article of commerce, 
lame <|ii;mtitirs brin^ used in taimiim. Sec i;,l,,,nn 
acorned (a'kornd), a. 1. Furnished or loaded 
with acorns. Specifically, in her. , said of an oak repre- 
sented on a coat of arms as loaded with acorns. 
2. Fed with acorns. Shak., Cymbeline, ii. 5. 
acorn-moth (a'korn-moth), n. A guest-moth, 
described as Holcocera glanduletta, but subse- 
quently referred to the genus Blastobasis, be- 
longing to the Tineidai. Its color is ash-gray, with 
two distinct spots near the middle of the fore wings and 
a transverse pale stripe across the basal third. Its larva is 
grayish-white, with a light-brown head and cervical and 
caudal shields, and is commonly met with in mast, feed- 
ing chiefly on those acorns that have been occupied by 
the acorn-weevil. See cut in preceding column. 
acorn-Oil (a'korn-oil), n. A volatile oil, of but- 
tery consistence and pungent odor, obtained 
from the acorns of Quercux robur. 
acorn-shell (a'k6rn-shel), n. 1. The shell of 
the acorn. 2. One of the cirripeds of the 
genus Balanus; a barnacle: called by this name 
trom a supposed resemblance of some of the 
species to acorns. See Balanus and Cirripedia. 
acorn-weevil (a'korn-we'vl), . The popular 
name for certain species of the curculionid ge- 
nus Balaninus, as B. uniformis (Le Conte), Ii. 
rectus (Say), and B. quercus (Horn), which live 
in the larval state within acorns. The females 
possess extremely long and slender beaks, by means of 
which they pierce the rind of the acorn and push an egg 
into the interior. The larva is a legless grub of elongate 
curved shape, not differing essentially from other curcu- 
lionid larva?. The affected acorn drops prematurely, and 
the full-grown larva eats its way out to change to a puna 
in the ground. See cut under Balamnus. 
acorn-worm (a'k6rn-werm), n. A name given 
to the Balanoglossus, the type and sole member 
of the order Enteropneusta : so called from the 
acorn-like shape of the anterior end of its body. 
See Balanoglossus, Enteropneusta. 
Acorns (ak'o-rus), n. [NL., < Gr. a/copof, the 
sweet-flag.] A genus of aromatic flag-like 
plants, natural order Aracece, of two species. 
A. Calamity, the Catamux aromaticux of druggists, is na- 
tive or widely naturalized in northern temperate regions, 
and is known as sweet-flag or sioeet-rush. See sweet-flag 
acpsmiat (a-koz'mi-S,), n. [NL., < Gr. aicoo/iia, 
disorder, < aKocftoi;, without order, < a- priv. + 
/too/for, order: see cosmos.'] 1. Irregularity in 
disease, particularly in crises. 2. Ill health, 
with loss of color in the face. 
acosmism (a-koz'mizm), n. [< Gr. a- priv. + 
K6a[ior, world, + -ism. Cf. acosmia.] The denial 
of the existence of an external world. Dean 
Mansel. 
acosmist (a-koz'mist), n. [As acosm-ism + -ist.] 
One who_ holds the doctrine of acosmism. 
acosmistic (ak-oz-mis'tik), a. Pertaining to 
the doctrine of acosmism. 
acotyledon (a-kot-i-le'don), n. ; pi. acotyledones, 
acotyledons (-le'do-nez, -donz). [=F. acotyle- 
done, < NL. acotyledo(n-)" (so. 
planta), a plant without seed- 
lobes, < Gr. a- priv. + KOTv^r/dorv, 
any cup-shaped cavity : see co- 
tyledon.] A plant destitute of 
a cotyledonous embryo. The 
name Acatyledonei was proposed by the 
younger Jnssieu for the class of plants 
which have no proper seed or embryo, 
now usually and more properly desig- 
nated as Ciyftaffamta or cryptogams. 
acotyledonous (a-kot-i-ie'do- 
nus), a. Without cotyledons, 
or seed-lobes, as the embryo 
otLuscuta; more usually, with- 
out embryo (and consequently ,M 
without cotyledons), as crypto- ( Frora Sachs's" 
acou-. For acu-. in words from Greek ammiv, 
hear: an irregular spelling due to the French 
spelling of acoustic, the first of these words in- 
troduced into English. See acoustic. 
acouchi-resin (a-ko'shi-rez^in), n. [Acouchi 
(alouclii, ahichi, etc.), native name (in F. spell- 
ing) in Guiana.] The inspissated juice of Pro- 
tium Aracouchini (Idea heterophylla), of Guiana, 
and other species of tropical South America. 
It resembles the elemi-resin of the old world, and is appli- 
cable to the same purposes. Also called alouchi-, aluchi-, 
or aracoiiflii ui-i-,'.<i a 
acquchy (a-kd'shi), . [< F. acouchi, agouehi, 
said to be from the native Guiana name.] An 
animal belonging to the genus Dasyprocta, 
family Dasyproctidce, of the hystricine series of 
the order /imlriiiiti ; the olive agouti or Surinam 
rat, Datyprocta acouchi/, inhabiting Guiana and 
some of the West India islands. It is related 
to the cavies, or guinea-pig family. See </""'' 
acquaint 
and J>itxi/i>riM-/iil,i: Also 
nci/c/ii. 
ni-niii-lii and 
Acouchy (Dasyprocta acoitchy). 
acoumeter (a-ko"- or a-kou'me-ter), n. [Also 
acouometei; irreg. < Gr"aKoi>eiv, hoar, + uirpov, a 
measure.] An instrument for measuring the 
power of the sense of hearing. Also called 
acousimeter. 
acoumetry (a-ko'- or a-kou'me-tri), . [Irreg. < 
Gr. (iKoiieiv, hear, + -ficrpia, < fierpov, a measure.] 
The measuring of the power of hearing. 
acousimeter (a-ko- or a-kou-sim'e-ter), n. [< 
Gr. amvaif, a hearing (< aKoiieiv, hear), + iierpav, 
a measure.] Same as acoumeter. 
acousmatic (a-kos- or a-kous-mat'ik), a. and n. 
[< Gr. imoasfuerticdf, willing to hear (oi anowua- 
TIKOI, the probationers of Pythagoras), < &KOVO- 
fta(r-), a thing heard, < iuanmv, hear: see acous- 
tic.] I. a. Hearing; listening: as, acousmatic 
disciples. 
II. n. A name given to such of the disciples 
of the Greek philosopher Pythagoras as had 
not completed their years of probation ; hence, 
a professed hearer; a probationer. 
An equivalent form is acoustic. 
acoustic (a-kos'- or a-kous'tik), a. and n. 
[Formerly acoustick, acoustique, < F. acoustique 
= Sp. Pg. It. acustico^. NL. acusticus, < Gr. O.KOV- 
crriKof, relating to hearing, < movaruf, heard, au- 
dible, < aKovuv, hear; cf. amt/, hearing, noelv, 
perceive; root prob.*w, *KOF, *CTKOF=L. cavere, 
heed, cautus, heedful (see caution), = Goth, us- 
skawjan, take heed, = AS. scedwian, look at, E. 
show, q. v. The regular E. form would be *acus- 
tic: geeacott-.] I. a. 1 . Pertaining to the sense 
or organs of hearing, or to the science of sound. 
2. Same as acousmatic. -Acoustic color, the tim- 
bre or quality of a musical note. See timbre. Acoustic 
duct, in anat., the meatus auditorius externus, or external 
passage of the ear. See auditory, and cut under earl. 
Acoustic nerve, the auditory nerve. Acoustic spot, 
macula acustica. See macula. Acoustic telegraph' 
an electric or mechanical apparatus for the reproduction 
of sounds at a distance. Acoustic tubercle (translation 
of luberculum aciuticum), in anat., a rounded elevation on 
either side of the floor of the fourth ventricle of the brain 
over which certain white lines, the stria; acustic, pass 
Acoustic vessel, acoustic vase, a bell-shaped vessel of 
bronze or pottery, of which a number, according to Vitru- 
vius, were built in beneath the seats, or placed in chambers 
prepared especially to receive them, in the auditorium of 
ancient theaters, to give sonorousness to the voices of the 
players. No such vessels have been recognized among the 
ruins of either Oreek or Roman theaters ; but it is said that 
similar vases were introduced for a like purpose in the 
vault of the choir of the medieval church of the Domini- 
cans at Strasburg. 
II. n. If. In med., a remedy for deaf ness or 
imperfect hearing. 2. Same as acousmatic. 
acoustical (a-kos'- or a-kous'ti-kal), a. Of or 
belonging to the science of acoustics ; acoustic. 
Theacuteness of the blind in drawing conclusions from 
slender acoustical premises. Science, VI. 195. 
acoustically (a-kos'- or a-kous'ti-kal-i), adv. 
In relation to acoustics or hearing. 
acoustician (a-kos- or a-kous-tish'an), n. One 
skilled in the science of sound; a student of 
acoustics. 
The transverse vibrations . . . were the only ones no- 
ticed by the earlier antiixtiriinis. 
Wheicell, Hist. Inductive Sciences, viii. 6. 
acoustics (a-kos'- or a-kous'tiks), n. [PI. of 
acoustic (see -ics) ; = Fl acoustique = Sp. Pg. It. 
acustica.] The science of sound; the study of 
the cause, nature, and phenomena of the vibra- 
tions of elastic bodies which affect the organ 
of hearing. The manner in which sound is produced 
its transmission through air and other media (sometimes 
called ttiatmitlicx), the theory of reflected sound, or echoes 
(sometimes called oodumutiu), the properties and effects 
of different sounds, including musical sounds or notes, and 
the structure and action of the organ of hearing, are all 
included in acoustics. See ftound. 
acq.ua (iik'wa), . [It.] See aqua. 
acquaint (a-kwanf), a. [Sc. acquaint, acquent, 
< ME. aquente, aqueynte, aqicynt, aquointe, < 
OF. acoint, later accoint, " acquainted or famil- 
