Source : Webster's Revised Unabridged Dictionary (1913)

Groundsel \Ground"sel\, n. [OE. grundswilie, AS. grundeswylige,
   grundeswelge, earlier gundiswilge; gund matter, pus + swelgan
   to swallow. So named as being good for a running from the
   eye. See {Swallow}, v.] (Bot.)
   An annual composite plant ({Senecio vulgaris}), one of the
   most common and widely distributed weeds on the globe.

Source : WordNet®

Senecio vulgaris
     n : Eurasian weed with heads of small yellow flowers [syn: {groundsel}]