1The alphabet; especially (in early use) the Roman alphabet as opposed to the Greek; (in later use) an alphabet belonging to an ancient writing system, or an inscription of this.
2In the work of British economist and logician W. S. Jevons: the series of possible combinations of letters in a system for solving logical problems; (also) the mechanical device invented by Jevons for generating and displaying these combinations.
3An alphabetical wordbook or wordlist, usually elementary; especially a primer for teaching the basics of reading and spelling.
Old English; earliest use found in Byrhtferð of Ramsey (fl. c986–c1016), Benedictine monk and scholar. From post-classical Latin abecedarium abecedary; compare -arium.