English, derived in the mid 18^th century, probably from the Latin name Emilia (possibly from "rival"), as is Emily.  Chambers suggests the meaning is "struggling" or "labour".

Until recently Amelia was mainly replaced by Emily. However, it is now increasing in popularity again.

There was a small but significant occurrence in Aberdeenshire in the 1841 Census. Rare re-spellings or variants include Amellia, Amilia, Emelia and Emilia.