'ruminative' originates from Latin, specifically the verb 'ruminare' and the past-participle stem 'ruminativus', where 'rumen' or 'rumis' referred to 'throat, gullet' and by extension 'cud'; 'ruminare' meant 'to chew the cud' or 'to chew over (meditatively)'.

'ruminative' developed via Late Latin forms such as 'ruminativus' (meaning 'given to chewing/meditation'), entered scholarly and literary English through the verb 'ruminate' (from Late Latin 'ruminare') in the 16th–17th centuries, and the adjective form 'ruminative' was formed in English to describe a meditative or contemplative quality.

Initially it referred literally to 'chewing the cud' (physical action), but over time it evolved figuratively to mean 'chewing over' ideas or thoughts — i.e., deep or repetitive thinking.