Definition of opponent for English Language Learners. : 1  a person, team, group, etc., that is competing against another in a contest. : 2  a person, group, etc., that is against something (such as an action, law, or system) : someone or something that does not want something to exist, be done, etc.
On the Celtic calendar, the traditional first day of winter is 1 November (Samhain, the Celtic origin of Halloween); spring starts 1 February (Imbolc, the Celtic origin of Groundhog Day); summer begins 1 May (Beltane, the Celtic origin of May Day); the first day of autumn is 1 August (Celtic Lughnasadh).
In some traditions, the first day of Christmas begins on the evening of December 25th with the following day considered the First Day of Christmas (December 26th). In these traditions, the twelve days begin December 26 and include Epiphany on January 6. The origin and counting of the Twelve Days is complicated, and is related to differences in calendars, church traditions, and ways to observe this holy day in various cultures (see Christmas).