1. A zodiacal constellation in the northern hemisphere between Taurus and Cancer on the ecliptic.
2. The third sign of the zodiac; the sun is in this sign from May 21 to June 20; Also called: Gemini the Twins.
Prominent zodiacal constellation in the northern hemisphere represented as the twins Castor and Pollux. Its brightest star is Pollux; Castor is a system of six stars. The Sun passes through Gemini from late June to late July. Each Dec, the Geminid meteors radiate from Gemini. In astrology, the dates for Gemini are between about 21 May and 21 June (see precession).