Easton's Bible Dictionary
(4.) Merorim, plural, "bitter herbs," eaten by the Israelites at the Passover (Exodus 12:8; Numbers 9:11). They were bitter plants of various sorts, and referred symbolically to the oppression in Egypt.
Noah Webster's New International Dictionary of the English Language
1. (n.) A plant whose stem does not become woody and permanent, but dies, at least down to the ground, after flowering.
2. (n.) Grass; herbage.