Noun
In Ancient Egypt, a heavy beaded necklace and musical instrument with a crescent-shaped plate in the front and a keyhole-shaped amuletic counterweight in the rear, considered sacred to Hathor.
The keyhole-shaped counterweight of such a necklace, considered an amulet to secure divine protection and to ensure fertility.
Source: en.wiktionary.orgI am not as these are, the poet saithIn youth's pride, and the painter, among menAt bay, where never pencil comes nor pem. Dante Gabriel Rossetti
A temple to Menat (an early Hathor ) at Thebes was oriented with reference to Spica when it was built in 3200 BC, and, over time, precession slowly but noticeably changed Spica's location relative to the temple. Source: Internet