1646, from Fr. médical, from L.L. medicalis "of a physician," from L. medicus "physician" (n.); "healing" (adj.), from mederi "to heal," originally "know the best course for," from PIE base *med- "to measure, limit, consider, advise" (cf. Gk. medos "counsel, plan, device, cunning," Avestan vi-mad "physician").

–noun, plural -ar·ies.

1.

a book containing a selection of the words of a language, usually arranged alphabetically, giving information about their meanings, pronunciations, etymologies, inflected forms, etc., expressed in either 134 the same or another language; lexicon; glossary: a dictionary of English; a Japanese-English dictionary.

2.	a book giving information on particular subjects or on a particular aa5 class of words, names, or facts, usually arranged alphabetically: a biographical dictionary; a dictionary of mathematics.

3.	Computers. a. a list of codes, terms, keys, etc., and their meanings, used by a computer program or system. b. a list of words used by a word-processing program as the standard against which to check the spelling of text entered.