vest, waistcoatIn American English, a sleeveless garment worn over a shirt is usually called a vest; in British English, a waistcoat is typically worn over a shirt and under a jacket.
SP: Lleva un chaleco negro sobre la camisa.
EN: He’s wearing a black vest over his shirt.
life jacketIn chaleco salvavidas, the phrase means “life jacket.”
SP: Ponte el chaleco salvavidas antes de subir al bote.
EN: Put on the life jacket before getting into the boat.