Geminorum

Geminorum is the genitive form of Gemini, the zodiacal constellation that represents the twins Castor and Pollux. In Latin astronomical nomenclature, Geminorum means “of the Twins” and is used as a suffix to indicate that a star or other object lies within the boundaries of Gemini. It is not the name of a specific object on its own.

The suffix appears most commonly in Flamsteed designations, where a numerical designation is paired with the Latin genitive of the constellation, yielding names such as 4 Geminorum. The form is also used in the naming of variable stars within Gemini, following the standard conventions for constellation-based variable-star designations. In these cases, Geminorum serves as a geographic indicator rather than as a distinctive proper name.

While the two brightest stars in Gemini have well-known traditional names (Pollux and Castor) and formal designations such as Alpha Geminorum and Beta Geminorum, many other stars in the constellation are identified primarily by Flamsteed or variable-star names that incorporate Geminorum. The suffix reflects a historical and cataloging convention that remains in use in literature and archives, even as modern official names often favor Bayer designations or widely recognized proper names.

See also: Gemini, Flamsteed designation, Bayer designation, Castor, Pollux.