English place surname from land + dun (hill), indicating a hill settlement.
Lanndon is an English place surname built from land and dun, meaning "hill," so the underlying sense is that of a hill settlement. That gives it a strong geographic and topographic character.
Lanndon feels solid and surname-like, with the kind of structure that often works well as a modern first name. It sounds grounded and substantial, but the doubled n makes it look more distinctive than the traditional form. The name has an easy confidence and a quiet sense of place.