"Toast": According to the n2 definition in the Oxford English Dictionary (2nd Ed., online):

[A figurative application of  TOAST n.1, the name of a lady being supposed to flavour a bumper like a spiced toast in the drink.
  See the Tatler, No. 24, of 2 June, and No. 31, of 18 June, 1709, in both of which toast is explained as a new name, upon the origin of which ‘the Learned differ very much’. No. 24 says that ‘many of the Wits of the last Age will assert’ that the term originated in an incident alleged to have occurred at Bath in the reign of Charles II, 1660-1684. No. 31 is silent as to the incident, and gives the account cited below.] 

    1. A lady who is named as the person to whom a company is requested to drink; often one who is the reigning belle of the season. Now only Hist.

1700 CONGREVE Way World III. x, More censorious than a decayed Beauty, or a discarded Toast. 1705 CIBBER Careless Husb. v. 63 Ay, Madam,..'t has been your Life's whole Pride of late to be the Common Toast of every Publick Table. 1709 STEELE Tatler No. 24¶9 This Whim gave Foundation to the present Honour..done to the Lady we mention in our Liquors, who has ever since been called a Toast. Ibid. No. 31 ¶8 Then, said he, Why do you call live People Toasts? I answered, That was a new Name found out by the Wits to make a Lady have the same Effect as Burridge in the Glass when a Man is drinking. Ibid. No. 71 ¶8 A Beauty, whose Health is drank from Heddington to Hinksey,..has no more the Title of Lady, but reigns an undisputed Toast. 1711 SWIFT Lett. (1767) III. 185 Lord Rochester, and his fine daughter, lady Jane, just growing a top toast. 1713 STEELE Guard. No. 85 ¶7 Was that the silly thing so much talked of? How did she ever grow into a toast? 1766 [C. ANSTEY] Bath Guide xi 34 'Tis she that has long been the Toast of the Town. 1779 F. BURNEY Diary Oct., The present beauty,..a Mrs. Musters,..the reigning toast of the season. 1822 W. IRVING Braceb. Hall iv. 35 She will often speak of the toasts of those days as if still reigning. 1888 BURGON 12 Gd. Men II. 346 He..described how very lovely she was..when she was a toast at Northampton.