late 14c., "ball of lead, plumb of a bob-line," from Old French plomet "graphite, lead; plummet, sounding lead," diminutive of plom "sounding lead" (see plumb (n.)).
plummet (v.)
1620s, "to fathom, take soundings," from plummet (n.). Meaning "to fall rapidly" first recorded 1933, perhaps originally among aviators. Related: Plummeted; plummeting.
plumbing
plumbo-
plumbous
plume
plumed
plummet
plump
plumpness
plunder
plunge
plunger
