'apposer' originates from Latin, specifically the word 'appōnere', where the prefix 'ad-' (often appearing as 'ap-' before 'p') meant 'to' and 'ponere' meant 'to place'.

'apposer' changed from Old French 'apposer' (from Medieval Latin forms such as 'apponere'/'appōnere') and eventually entered English in the form of the verb 'appose' and the derived noun 'apposer'.

Initially it meant 'to put or place to/near (something)', but over time it evolved into the current sense 'to place side by side, especially in apposition'.