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).
Many folks assume the first day of spring in the Northern Hemisphere â also known as the vernal equinox â has always come on March 21. But this year seems to be an exception, for in 2013 the first day of spring comes on Wednesday, March 20 at 11:02 UT, or 7:02 a.m. EDT/4:02 a.m. PDT. Now this doesn't seem right.