Definition - An alphabetical list of glosses — i.e. unusual or obscure words that need explanation.

Example -
How to Speak East Enders: A Brief Glossary of Cockney Expressions.

Etymology -
The word derives from the Latin glossarium, collection of glosses, which in turn derives from the Greek glossarion, the diminutive of glossa, obsolete or foreign word.

Oxford English Dictionary -
Its first citation is from 1380:
"As seiþ þe bok, iclept Glosarie."
(S. Paula 36 in Horstm. Altengl. Leg. (1878) 8)

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