v. i. [ imp. & p. p. Simmered p. pr. & vb. n. Simmering. ] [ Prov. E. also simper; -- an onomatopoetic word. ] To boil gently, or with a gentle hissing; to begin to boil. [ 1913 Webster ]
I simmer as liquor doth on the fire before it beginneth to boil. Palsgrave. [ 1913 Webster ]