The Collaborative International Dictionary of English v.0.48:
Mugwort \Mug"wort`\, n. [AS. mucgwyrt. Cf. Midge.] (Bot.) A somewhat aromatic composite weed (Artemisia vulgaris), at one time used medicinally; -- called also motherwort. [1913 Webster]WordNet (r) 3.0 (2006):
mugwort n 1: any of several weedy composite plants of the genus Artemisia