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. The letters n+m from both words are assimilated to long mm

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.