'Columbus Day' definitions:

Definition of 'Columbus Day'

(from WordNet)
noun
A legal holiday commemorating the discovery of America by Christopher Columbus [syn: Columbus Day, Discovery Day, October 12]

Definition of 'Columbus Day'

From: GCIDE
  • Columbus Day \Co*lum"bus Day\ The 12th day of October, on which day in 1492 Christopher Columbus discovered America, landing on one of the Bahama Islands (probably the one now commonly called Watling Island), and naming it "San Salvador"; -- called also Discovery Day. This day is made a legal holiday in many States of The United States. [Webster 1913 Suppl.]