Elemmírë

Elemmírë was one of the lights kindled by Varda far in the past, to welcome the Elves to Arda on their awakening. It is described in Quenta Silmarillion as a star, but in fact it was most likely identified with one of the planets.

Etymology

Elemmírë means "star-jewel". It's a compound from elen and mírë

Inspiration

Tolkien's notes on the subject are open to interpretation, but they appear to identify Elemmírë as the planet we know today as Mercury.