'before-sunrise' originates from Old English elements: 'beforan' (Old English) meaning 'before' and the compound 'sunrise' formed from Old English 'sunne' ('sun') + 'rīsan' ('to rise').

'before' comes from Old English 'beforan' (meaning 'in front of, before'); 'sunrise' is a later compound of Old English 'sunne' + 'rīsan'. The modern hyphenated phrase 'before-sunrise' is a transparent modern English compound built from these parts.

Initially it simply expressed temporal relation 'before the sun rose'; over time the compound form (and related single-word synonyms like 'predawn') have been used stylistically, but the core temporal meaning has remained the same.