1 a the expression of gratitude, esp. to God. b a form of words for this.
2 (Thanksgiving or Thanksgiving Day) a national holiday for giving thanks to God, the fourth Thursday in November in the US, usu. the second Monday in October in Canada.
Phrases and idioms:
General Thanksgiving a form of thanksgiving in the Book of Common Prayer or the Alternative Service Book.

Useful english dictionary. 2012.