'atsara' originates from Tagalog/Filipino, specifically the word 'atsara' (also spelled 'atchara'), which ultimately traces to Malay/Indonesian 'acar' meaning 'pickle' (via South Asian sources).

'atsara' changed through contact with Malay/Indonesian 'acar' and Spanish forms such as 'achara'/'atchara' during colonial and trade periods, and the term was adopted into English usage as a name for the Filipino pickle.

Initially it referred more generally to pickled foods (as in Malay/Indonesian 'acar'), but in Filipino usage it became associated specifically with the sweet-and-sour pickled green papaya now called 'atsara'.