What is a constituent?

Definition
	A constituent is one of two or more grammatical units that enter syntactically or morphologically into a construction at any level.

Examples (English)
	The sentence You eat bananas contains the following constituents: Immediate constituents you eat bananas Ultimate constituents you eat banana -s

Kinds
	Here are some kinds of constituents:
	What is an immediate constituent? What is an ultimate constituent? What is a construction? What are discontinuous constituents? What is a morpheme? What is a zero?