'predawn' is formed from the prefix 'pre-' (from Latin 'prae', meaning 'before') + 'dawn' (Old English 'dagian'/'dag', related to 'day').

'dawn' comes from Old English words such as 'dagian' (to become day) and 'dag' (day). The modern combination 'pre-' + 'dawn' developed in Modern English to mean the time before daybreak.

Originally built simply as a compound meaning 'before dawn'; its basic meaning — the time just before sunrise — has remained stable.