'Isabella' originates from Medieval Latin and Old Spanish/Italian, specifically the name 'Isabel' (Old Spanish) and Italian 'Isabella', where the ultimate source is Hebrew 'Elisheba' meaning 'God is my oath' or 'God is abundance'.

'Isabella' changed from the Old Spanish name 'Isabel' (itself from Latin 'Elisabeth'), and through medieval Italian and Spanish forms (e.g. 'Isabella', 'Isabel') eventually entered modern English as 'Isabella'.

Initially it transmitted the Hebrew theophoric sense 'God is my oath' (from 'Elisheba'), but over time it became used primarily as a personal name without carrying the literal religious phrase in everyday use.