This character is a Other Symbol and is commonly used, that is, in no specific script.
The glyph is not a composition. Its East Asian Width is wide. In bidirectional text it acts as Other Neutral. When changing direction it is not mirrored. The word that U+2651 forms with similar adjacent characters prevents a line break inside it.
The CLDR project calls this character “Capricorn” for use in screen reading software. It assigns these additional labels, e.g. for search in emoji pickers: goat, horoscope, zodiac.
This character is designated as an emoji. It will be rendered as colorful emoji on conforming platforms. To reduce it to a monochrome character, you can combine it with Variation Selector-15: ♑︎ See the Emojipedia for more details on this character’s emoji properties.
The Wikipedia has the following information about this codepoint:
Capricorn(♑︎) (Greek: Αιγόκερως, romanized: Aigókerōs, Latin for "horned goat") is the tenth astrological sign in the zodiac out of twelve total zodiac signs, originating from the constellation of Capricornus, the goat. It spans the 270–300th degree of the zodiac, corresponding to celestial longitude. Under the tropical zodiac, the sun transits this area from around December 22 to January 19. Capricorn is one of the three earth signs, alongside Virgo and Taurus, a negative sign, and one of the four cardinal signs. Capricorn is ruled by the planet Saturn and its opposite sign is Cancer.