'PPD' originates from modern English as an initialism formed from the initial letters of the multiword term 'postpartum depression' (for the psychiatric sense). The element 'post-' comes from Latin 'post' meaning 'after', and 'partum' traces to Latin 'partus' meaning 'birth'.

'postpartum depression' emerged in 20th-century medical literature to name depressive episodes occurring after childbirth; the reduced form 'PPD' arose later as a convenient abbreviation in clinical and informal usage.

Initially, the components 'post-' and 'partum' simply meant 'after' and 'birth' respectively; over time the combined phrase 'postpartum depression' came to denote the clinical condition, and 'PPD' now commonly denotes that condition or other established abbreviations such as 'purified protein derivative' or 'p-phenylenediamine' depending on context.