1. (Science: zoology) A hedgehog.
4. A pert or roguish child; now commonly used only of a boy. And the urchins that stand with their thievish eyes Forever on watch ran off each with a prize. (W. Howitt) You did indeed dissemble, you urchin you; but where's the girl that won't dissemble for an husband? (goldsmith)
Origin: OE. Urchon, irchon, a hedgehog, OF. Irecon, ericon, herion, herichon, F. Herisson, a derivative fr. L. Ericius, from er a hedgehog, for her; akin to Gr. Cf. Herisson.