- 1a widely distributed plant of the daisy family, with yellow rayless flowers.
- Genus Senecio, family Compositae: several species, in particular the common groundsel (S. vulgaris), which is a common weed. See also giant groundsel
- 2variant spelling of groundsill.
Old English gundæswelgiæ (later grundeswylige), probably from gund 'pus' + swelgan 'to swallow' (with reference to its use in poultices). The later form may be by association with ground1, and refer to the plant's rapid growth