convex lens

English Thesaurus

1. lens such that a beam of light passing through it is brought to a point or focus (noun.artifact)

hypernym	:	lens, lens system, lense,
definition	:	a transparent optical device used to converge or diverge transmitted light and to form images (noun.artifact)

hyponym	:	sunglass,
definition	:	a convex lens that focuses the rays of the sun; used to start a fire (noun.artifact)