'appender' originates from Latin, specifically the word 'appendere', where the prefix 'ad-' meant 'to/toward' and 'pendere' meant 'to hang'.

'appendere' passed into Middle English and Anglo-Norman forms (via Old French influences such as 'apendre'/'apender'), and the verb 'append' developed in English; the noun 'appender' later formed by adding the agentive suffix '-er'.

Initially, the root meant 'to hang onto or attach'. Over time it came to mean 'to add (something) to the end of another thing', a sense maintained in modern English and extended into technical contexts (e.g., computing).