What is "to drink to"

Drink \Drink\ (dr[i^][ng]k), v. i. [imp. Drank (dr[a^][ng]k), formerly Drunk (dr[u^][ng]k); & p. p. Drunk, Drunken (-'n); p. pr. & vb. n. Drinking. Drunken is now rarely used, except as a verbal adj. in sense of habitually intoxicated; the form drank, not infrequently used as a p. p., is not so analogical.] [AS. drincan; akin to OS. drinkan, D. drinken, G. trinken, Icel. drekka, Sw. dricka, Dan. drikke, Goth. drigkan. Cf. Drench, Drunken, Drown.]

1. To swallow anything liquid, for quenching thirst or other purpose; to imbibe; to receive or partake of, as if in satisfaction of thirst; as, to drink from a spring.

   Gird thyself, and serve me, till have eaten and drunken; and afterward thou shalt eat and drink.
   --Luke xvii. 8.

   He shall drink of the wrath the Almighty.
   --Job xxi. 20.

   Drink of the cup that can not cloy.
   --Keble.

2. To quaff exhilarating or intoxicating liquors, in merriment or feasting; to carouse; to revel; hence, to lake alcoholic liquors to excess; to be intemperate in the ?se of intoxicating or spirituous liquors; to tipple.
   --Pope.

   And they drank, and were merry with him.
   --Gem. xliii. 34.

   Bolingbroke always spoke freely when he had drunk freely.
   --Thackeray.

   To drink to, to salute in drinking; to wish well to, in the act of taking the cup; to pledge in drinking.

   I drink to the general joy of the whole table, And to our dear friend Banquo.
   --Shak.