wedge1
Pronunciation: /wɛdʒ/
noun
- 1a piece of wood, metal, etc. having one thick end and tapering to a thin edge, that is driven between two objects or parts of an object to secure or separate them: the door was secured by a wedge
- an object or piece of something shaped like a wedge: a wedge of cheese
- a formation of people or animals in the shape of a wedge: the wedge of horsemen crashed forward
verb

Phrases
-
drive a wedge between
- separate: the general aimed to drive a wedge between the city and its northern defences
- cause disagreement or hostility between: I’m not trying to drive a wedge between you and your father
-
the thin end of the wedge
- informal an action or procedure of little importance that is likely to lead to more serious developments: a charge for nursery classes would be the thin end of the wedge and lead to charges for ordinary schooling

Origin:
Old English wecg (noun), of Germanic origin; related to Dutch wig