toast¹ / tōst/ • n. 1. sliced bread browned on both sides by exposure to radiant heat.2. a call to a gathering of people to raise their glasses and drink together in honor of a person or thing, or an instance of drinking in this way: he raised his glass in a toast to his son. ∎  [in sing.] a person or thing that is very popular or held in high regard by a particular group of people: he found himself the toast of the baseball world. • v. [tr.] 1. cook or brown (food, esp. bread or cheese) by exposure to a grill, fire, or other source of radiant heat: he sat by the fire and toasted a piece of bread | [as adj.] (toasted) toasted marshmallows. ∎  [intr.] (of food) cook or become brown in this way: broil until the nuts have toasted. ∎  warm (oneself or part of one's body) in front of a fire or other source or heat.2. drink to the health or in honor of (someone or something) by raising one's glass together with others: happy families toasting each other's health| fig. he is toasted by the trade as the outstanding dealer in children's books. PHRASES: be toast inf. be or be likely to become finished, defunct, or dead: one mistake and you're toast.toast² • v. [intr.] [usu. as n.] (toasting) (of a DJ) accompany a reggae backing track or music with improvised rhythmic speech.DERIVATIVES: toast·er n.

toast sliced bread browned on both sides by exposure to heat; the practice of drinking a toast in honour of a person or thing goes back to the late 17th century, and originated in naming a lady whose health the company was requested to drink, the idea being that the lady's name flavoured the drink like the pieces of spiced toast that were formerly placed in drinks such as wine.
be toast be (or be likely to become) finished, defunct, or dead.
have someone on toast be in a position to deal with someone as one wishes; with reference to a food item served up on a slice of toast.

toast2 orig. favourite lady whose health is drunk to. XVII. Said to have been so named as being supposed to flavour the bumper like a spiced toast (TOAST1) in drink.

toast1 parch XVI; brown (bread, etc.) by exposure to heat XIV. — OF. toster roast, grill :- Rom. *tostāre, f, tost-, pp. stem of L. torrēre parch.
Hence sb. toasted bread. XV.