A sharp, pointy object, such as a sliver or splinter. / A bur; a seed pod with sharp features that stick in fur or clothing. / A small piece of material left on an edge after a cutting operation.

(biology) Any organism found in surroundings, or in association with another organism, in which it is normally absent

(organic chemistry) An alkaloid found in ragwort (Jacobaea vulgaris).

plural of certification