Cases of word usage

1) (a kind of, wood of) a tree with smooth, bright reddish-brown nuts (some being edible) (chestnut)

2) the hard outer covering of eggs, nuts some seeds etc and of some animals (e.g. snails, crabs) or parts of them; seashell; the outside walls etc of a building, ship etc (shell)

3) a kind of tool used for gripping and turning nuts on screws, bolts etc (US = wrench) (spanner)