What does "urchin" mean?

Additional senses

1. 2.A mischievous elf supposed sometimes to take the form a hedgehog. "We 'll dress [them] like urchins, ouphes, and fairies." Shak.
2. 3.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.
3. 4.One of a pair in a series of small card cylinders, arranged around a carding drum; -- so called from its fancied resemblance to the hedgehog. Knight. Urchin fish (Zoöl.), a diodon.
4. 5.Rough; pricking; piercing. [R.] "Helping all urchin blasts." Milton.