'approbation' originates from Latin, specifically the word 'approbatio', where 'approbare' meant 'to approve' (from ad- 'to' + probare 'to test, prove').

'approbation' came into English via Late Latin 'approbatio' and Medieval Latin 'approbatio(n-)', passing through Middle French and Middle English to become the modern English 'approbation' (plural 'approbations').

Initially, it meant 'the act of approving or testing (approval)', and over time it kept that core sense while extending to mean 'praise' and 'formal/official approval' in modern usage.