The evolution of dictionaries has been the result of a long process of development over many centuries

The course of dictionary development is marked by a relatively small number of epoch-making works, each of which held the field, directly or indirectly, through revisions and imitations over many years.

The name "dictionary", from dictionarius (liber) or dictionarium, originally meant a "word-book". It had as rivals numerous other terms, such as "lexicon" (the Greek form of "word-book"), "glossary, vocabulary", etc.

"Dictionary" is not only the most common designation of a word-book, but it is extended to other handbooks alphabetically arranged, such as dictionaries of antiquities, of quotations, of biography, and similar works.

Even the alphabetical order, or "dictionary order" as it is sometimes called, which seems to us so obviously the best, had a long contest with the arrangement by subjects or classes, and was not universally adopted until toward the end of the sixteenth century.

The alphabetical arrangement itself passed through various stages, beginning with lists of words having the same initial letter but not otherwise differentiated, passing to lists alphabetized by the first two letters, and culminating in our present system.

Dictionaries are in general of two kinds:

1. Those in which the words of one language are defined in terms of another.
2. Those in which the words of a language are explained or defined in the same tongue.

The former become necessary when foreign languages are studied, the latter when a speech has reached such a stage of development as to contain so many words which are not readily understood by the general public. The first word-books were the glossaries used by the Greek schoolboys of the fifth century before our era, to master the meanings of the obsolete and poetic words in their national reading-book, the poems of Homer.

These glossaries were gradually expanded and amplified until Philetas of Cos, who lived between 325 and 265 B.C., compiled what might be called the first Homeric Lexicon. As time went on, other special lexicons were made, and finally, toward the end of the first century of our era, the first general Greek Dictionary was begun by Zophyrion and completed by Pamphilus of Alexandria.

Similar educational conditions existed among the Romans, and the glossaries made to explain unfamiliar words led at last to the great dictionary of Verrius Flaccus, during the time of Augustus. This dictionary was so large that it was twice abridged, by Sextus Pompeius Festus and Paulus Diaconus. Only the latter has been preserved, along with some portions of the earlier epitome of Festus.

Festus is known only as a Latin grammarian who lived in the latter part of the third century and who made an abridgment of Verrius' work. What remains of Festus' abridgment exist only in one incomplete manuscript copy, the Codex Festi Farnesianus, in Naples, Italy.

Verrius illustrated the meanings and uses of words by quotations, which gave the work its principal value for modern scholars, and also introduced some encyclopedic material.

It will be seen that much of the ground gained in the course of so many centuries was lost during the Dark Ages, and that our English dictionaries practically started again at the beginning and passed through the same stages of growth, although at last they far outstripped their prototypes in the ancient world.