1921, "mass of fine particles," diminutive of flocculus (see flocculate).
Entries linking to floc
flocculate v.
"gather in flocculent masses," 1845 (flocculated), from flocculus (1799), from Modern Latin, a diminutive of Latin floccus "tuft of wool," a word of unknown origin, + -ate (2). Related: Flocculating.