'p-methoxybenzaldehyde' is a systematic chemical name composed of the prefix 'p-' (abbreviation of 'para-', from Greek 'para-' meaning 'beside'), 'methoxy' (from 'methyl' + 'oxy', indicating an OCH3 substituent), and 'benzaldehyde' (from 'benz-' referring to benzene/benzoin and 'aldehyde').

'benzaldehyde' derives from 'benzoin' (a resin name adopted into European languages) and the suffix 'aldehyde' (coined in the 19th century from Latin/German roots related to 'alcohol dehydrogenatus'); 'methoxy' is formed from 'methyl' (Greek/modern chemistry usage) + 'oxy' (from oxygen). These parts combined in modern chemical nomenclature to produce 'p-methoxybenzaldehyde' (also systematically named '4-methoxybenzaldehyde').

Originally the components referred separately to structural fragments (e.g., 'benzaldehyde' as the parent aromatic aldehyde and 'methoxy' as an OCH3 group); over time the combined systematic name came to denote the specific compound with a methoxy group at the para position, used as a standard name in organic chemistry.