The term 'day-active' combines 'day,' from Old English 'dæg,' meaning 'daylight,' and 'active,' from Latin 'activus,' meaning 'engaged in action.'

'Day' from Old English 'dæg' and 'active' from Latin 'activus' were combined in modern English to form 'day-active.'

Initially, 'day' referred to the period of daylight, and 'active' meant 'engaged in action.' Together, they describe organisms that are active during daylight hours.