To the eyes of Mr. Jeremiah Cruncher, sitting on his stool in Fleet Street with his grisly urchin beside him, a vast number and variety of objects in movement were every day presented.
A Tale of Two Cities (1866)
I actually discovered quite a bit about the meaning and history of the term urchin, often used in Victorian times for orphans or desperately poor children. Apparently, the first urchins were hedgehogs.
c. 1300, yrichon "hedgehog," from Old North French *irechon from Old French herichun "hedgehog" (Modern French hérisson), formed with diminutive suffix -on + Vulgar Latin *hericionem, from Latin ericius "hedgehog," enlarged form of er, originally *her, from PIE root *ghers- "to bristle".
Sometime around the mid-15th century, the English stopped calling these small mammals covered in bristles "urchins" and decided that they looked like piglets that typically lived in shrubs. According to Etymonline, the term hedgehog is a compound word formed by hedge (n.) and hog (n.)
The 15th-century hog seems to have been the clipped variant of the earlier 14th-century hoggaster “a boar in its third year” However, in some parts of Northern England and the West Midlands, these spiky rodent-like creatures are still called urchins
Still used for "hedgehog" in non-standard speech in Cumbria, Yorkshire, Shropshire.
The term urchin was eventually applied to anyone or anything that resembled a “hedgehog”
…hunchbacks (1520s) to goblins (1580s) to bad girls (1530s);
Sea urchin is recorded from 1590s (a 19c. Newfoundland name for them was whore's eggs); Johnson describes it as "a kind of crabfish that has prickles instead of feet."
And a street urchin is a young, grubby-looking child dressed in tattered clothes, who roams the city slums.
meaning "poorly or raggedly clothed youngster" emerged 1550s, but was not in frequent use until after c. 1780.
The Google Ngram below, compares the trends of urchin with sea urchin and the hyphenated sea-urchin in the British English corpus.
Despite what I have uncovered so far, I would like to know more
Today, it's my impression that the term urchin evokes pity and compassion. Was it always like that? Was the term “urchin” derogatory in the late 18th and 19th century? See the opening quotation.
Who or what sparked the trend circa 1780?
I thought it might have been Charles Dickens, but he was born in 1812 and he wrote and published Oliver Twist (the world's most famous urchin) as a serial between 1837 and 1839.