How do you spell Hannukah?
1580s, "lump; cluster of trees," from Middle English clompe "a lump" (c.1300), from Dutch klomp "lump, mass," or Middle Low German klumpe "clog, wooden shoe." Old English had clympre "lump, mass of metal."
"to heap or gather in clumps" (transitive), 1824, from clump (n.). Related: Clumped; clumping. Intransitive sense "to form a clump or clumps" is recorded from 1896.
"walk heavily," 1660s, imitative. Related: Clumped; clumping.
clumping clump·ing (klŭm'pĭng)
The massing together of bacteria or other cells suspended in a fluid.