noun

• (Canada, US) A sleeveless garment that buttons down the front, worn over a shirt, and often as part of a suit; a waistcoat.
  "The Jones man was looking at her hard. Now he reached into the hatch of his vest and fetched out a couple of cigars, everlasting big ones, with gilt bands on them."
• (British) A sleeveless garment, often with a low-cut neck, usually worn under a shirt or blouse.
• (now rare) A loose robe or outer garment worn historically by men in Arab or Middle Eastern countries.

verb

• (chiefly passive) To clothe with, or as with, a vestment, or garment; to dress; to robe; to cover, surround, or encompass closely.
  "Came vested all in white, pure as her mind."
• (law) To clothe with possession; also, to give a person an immediate fixed right of present or future enjoyment of.
  "to vest a person with an estate"
• (law, intransitive) (of an inheritance or a trust fund) To devolve upon the person currently entitled when a prior interest has ended.
  "Upon the death of the Sovereign the Crown automatically vests in the next heir without the need of coronation or other formality."
• (finance, intransitive) To become vested, to become permanent.
  "My pension vests at the end of the month and then I can take it with me when I quit."