Webbed describes feet, toes or fingers that have skin stretched between them. A duck has webbed feet. A frog has webbed toes. It is the everyday way to say it — 'ducks have webbed feet' is the sentence you will hear and use, much more than 'ducks are web-footed'.

It is also the word doctors use about people. Some babies are born with webbed fingers or webbed toes, where two of them are joined by skin. The medical name is syndactyly, but even doctors say 'webbed' when they talk to families, because it is clear.

The picture behind it is the old meaning of web: a thin flat sheet stretched across a gap. Same picture in a spider's web, same picture in the skin between a duck's toes.

One useful note. 'Webbed' almost always sits right before a body-part word — webbed feet, webbed toes, webbed fingers, webbed hands. If you take it away from body parts and say 'a webbed chair', that is a different thing entirely (chairs use webbing — see that word). So keep webbed for feet and hands.