whortleberry (n.)

common name of various plants bearing small blue, red, or black berries, 1660s, American English, probably an alteration of Middle English hurtilbery "whortleberry" (15c.), from Old English horte "whortleberry." Technically the fruit and plant of Gaylussacia, but also widely colloquially applied to the closely related blueberry (Vaccinium).

It figured in various colloquial American phrases, meaning sometimes "person or thing of little consequence" (1835), which seems to be the sense that inspired "Mark Twain's" character name (in comparison to Tom Sawyer), but also "that which is just right." Huckle as a dialect word meaning "hip" is from 1520s in English, from Low German.