'St Valentine's Day' definitions:

Definition of 'St Valentine's Day'

(from WordNet)
noun
A day for the exchange of tokens of affection [syn: Valentine Day, Valentine's Day, Saint Valentine's Day, St Valentine's Day, February 14]

Definition of 'St Valentine's Day'

From: GCIDE
  • Valentine \Val"en*tine\, n.
  • 1. A sweetheart chosen on St. Valentine's Day. [1913 Webster]
  • 2. A letter containing professions of love, or a missive of a sentimental, comic, or burlesque character, sent on St. Valentine's Day. [1913 Webster]
  • St. Valentine's Day, a day sacred to St. Valentine; the 14th of February. It was a very old notion, alluded to by Shakespeare, that on this day birds begin to mate. Hence, perhaps, arose the custom of sending love tokens at that time. [1913 Webster]