urchin

Etymology

From Middle English yrchoun, irchoun (“hedgehog”), borrowed from Old Northern French irechon, from Vulgar Latin *ērīciōnem, from Latin ericius. Compare modern French hérisson, whence the English doublet herisson.

noun

1. A mischievous child.
2. A street urchin, a child who lives, or spends most of their time, in the streets.
   And the urchins that stand with their thievish eyes / Forever on watch ran off each with a prize. a. 1879, William Howitt, The Wind in a Frolic
3. A sea urchin.
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.
   Here we have a carding-engine, with the drum surmounted with urchin or squirrel cards[…] 1836, Andrew Ure, The Cotton Manufacture of Great Britain[…]
5. (historical) A neutron-generating device that triggered the nuclear detonation of the earliest plutonium atomic bombs.
6. (obsolete) A hedgehog.
7. (obsolete) A mischievous elf supposed sometimes to take the form of a hedgehog.