Definitions
1.verbTo make thicker (in the sense of wider).
2.verbTo make thicker (in the sense of more viscous)."to thicken a sauce"
3.verbTo become thicker (in the sense of wider).
4.verbTo become thicker (in the sense of more viscous).
5.verbTo strengthen; to confirm.
6.verbTo make more frequent."to thicken blows"
7.nounThe process of making something, or becoming, thick or viscous.
8.nounA substance, usually a source of starch, used to thicken a sauce.
9.nounA thickened part of a structure.