A side-lock. See first quotation.

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a. 1838.  It was the fashion of the boys at the Leasburg Academy to wear their hair cut short behind—shingled, it would be called now—and long in front, coming down, when parted, below the ears, sometimes as far as the collar. These were called “soap locks,” the name being derived from the saponaceous material which was not infrequently applied to paste them in position.—J. H. Claiborne, ‘Seventy-Five Years in Old Virginia,’ p. 26 (1904).

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1840.  Soap-locks and short petticoats will shortly be banished.—Daily Pennant, St. Louis, June 25.

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1840.  The cambric ruffles had vanished, the watch-chains had disappeared, the soap-lock had cut him, or had been cut by him.—New Orleans Picayune, Oct.

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1842.  Just fancy Bill, with his small head topped by a weatherbeaten hat, and his gin-bloated face relieved by two greasy soap-locks.—Phila. Spirit of the Times, April 6.

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1853.  See HOOSIER.

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1857.  I felt her raven tresses mingling with my own ‘soap-locks,’ and while her precious breath was perfuming my whiskers, a scarcely audible whisper in reply, made me perhaps the ‘happiest man out of jail!’—Knick. Mag., l. 443 (Nov.).

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1891.  So as to give their disheveled soap locks a peculiarly forky and warlike appearance.—Oregon Argus, Aug. 10.

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