PREFACE. xiii 
both accuracy and homogeneity has, perhaps, never before been so fully adopted and faithfully applied 
in a dictionary. A few special explanations are necessary with regard to the work in several of the 
technical departments. 
To the biological sciences a degree of prominence has been given corresponding to the remarkable 
recent increase in their vocabulary. During the last quarter of a century there has been an extensive 
reorganization and variation of the former systems of classification, from which have come thousands 
of new names of genera, families, etc.; and also a profound modification of biological 
conceptions, which has led both to new definitions of old words and to the coinage of many The bi _ 1 < i < 1 
new words. All these terms that are English in form, and for any reason worthy of record, 
have been included, and also as many of the New Latin names of classificatory groups as are essential 
to a serviceable presentation of zoology and botany. The selection of the New Latin names in zoology 
has been liberal as regards the higher groups, as families, orders, etc., whether now current or merely 
forming a part of the history of the science ; but of generic names' only a relatively small number have 
been entered. Probably about 100,000 names of zoological genera exist, 60,000 at least having a definite 
scientific standing ; but the whole of them cannot, of course, be admitted into any dictionary. The 
general rule adopted for the inclusion of such names is to admit those on which are founded the names 
of higher groups, especially of families, or which are important for some other special reason, as popular 
use, an established position in works of reference, the existence of species which have popular English 
names, etc. A similar rule has been adopted with regard to botanical names. The common or ver- 
nacular names of animals and plants have been freely admitted ; many naturalized and unnaturalized 
foreign names, also, which have no English equivalents and are noteworthy for special literary, com- 
mercial, or other reasons, have been included. The definitions that have a purely scientific interest 
have been written from a technical point of view, the more popular information being given under 
those technical names that are in familiar use or under common names. In the zoological department 
is properly included anatomy in its widest sense (embracing embryology and morphology), as the science 
of animal structure, external and internal, normal and abnormal. Its vocabulary necessarily includes 
many Latin, or New Latin, words and phrases which have no English technical equivalents. 
The definitions of that part of general biological science which in any way relates to animal life 
or structure, including systematic zoology, have been written by Dr. Elliott Coues, who has been assisted 
in ichthyology and conchology by Prof. Theodore N. Gill, in entomology by Mr. Leland O. Howard 
and Mr. Herbert L. Smith, and in human anatomy by Prof. James K. Thacher. Special aid has also 
been received from other naturalists, particularly from Prof. Charles V. Riley, who has furnished a 
number of definitions accompanying a valuable series of entomological cuts obtained from him. Prof. 
Thacher has also defined all terms relating to medicine and surgery. The botanical work was under- 
taken by Dr. Sereno Watson, with assistance, in cryptogamic botany, from Mr. Arthur B. Seymour, and 
has been conducted by him through the letter G ; at that point, on account of practical considerations 
connected with his official duties, he transferred it to Dr. Lester F. Ward. Mr. Seymour also withdrew, 
his work passing, under Dr. Ward's editorship, to Prof. Frank H. Knowlton. All the definitions of the 
terms of fossil botany have been written by Prof. J. D. Whitney. 
In the treatment of the physical and mathematical sciences an equally broad method has been adopted. 
While their growth has, perhaps, not been so great, from a lexicographical point of view, as has that of 
biology, it is certainly almost as remarkable. The remodeling and readjustment of former ideas, and 
the consequent modification of the senses of old terms and the coinage of new, have 
been hardly less marked; while one department, at least that of chemistry has kept The physical and 
pace in the invention of names (of chemical compounds) with zoology and botany. To sciences, 
this must be added the almost numberless practical applications of the principles and 
results of physical science. The department of electrotechnics is a marked example of the formation 
within a comparatively few years of a large technical vocabulary, both scientific and mechanical. The 
adequate definition of all the lexicographical matter thus furnished involves a very complete presenta- 
tion of the present status of human knowledge of these sciences. The definitions in physics have been 
