'appositive' originates from Latin, specifically the word 'appositus' (past participle of 'apponere'/'adponere'), where 'ad-' meant 'to/toward' and 'ponere' meant 'to place'.

'appositus' passed into Late Latin as 'appositivus' and Old French/Medieval Latin forms, then entered Middle English as 'appositive' and later formed the adverb 'appositively' in modern English.

Initially it meant 'placed beside' (literally 'put toward'), and over time the term came to be used grammatically for elements placed beside nouns for identification or explanation; the adverb developed to describe that manner ('in an appositive way').