thanksgiving [thaŋks΄giv′iŋ]
a) the act of giving thanks
b) an expression of this; esp., a formal, often public, expression of thanks to God in the form of a prayer, etc.
2. [T-]
a) an annual U.S. holiday observed on the fourth Thursday of November as a day of giving thanks and feasting: it commemorates the Pilgrims' celebration of the good harvest of 1621
b) a similar Canadian holiday on the second Monday of October: in full Thanksgiving Day

English World dictionary. . 2014.