English place-name surname meaning 'Allen's farmstead', from Old Norse 'bý' (settlement).
Allenby began as an English surname and place-name formation, meaning 'Allen's farmstead' through the Old Norse element bý, 'settlement.' That makes it part of a long English tradition of names that preserve traces of medieval landholding, Norse influence, and regional geography.
As with many surnames turned given names, its original sense is rooted in place and family identity rather than in the kind of symbolic meaning found in later invented names. As a first name, Allenby feels sturdy, surname-like, and quietly distinguished. It has the composure of an established English name without being common, which gives it a slightly formal, tailored atmosphere.
Because it retains the rhythm of a family name, it can suggest heritage, steadiness, and a slightly old-world polish. Its rarity only strengthens that impression, making Allenby feel deliberate rather than casual.