'Eternal' and 'forever' are synonymous, but there is a subtle difference. 'Forever' refers to an endless or seemingly endless period of time. 'Eternal' means always lasting without a beginning or end; think of 'eternal' as existing outside of time. If something is eternal, it always is and always was.

eternal does mean forever. they are synonyms. there is no difference but the word itself...if you understand what i mean.