plummet

Meanings

1. A piece of lead attached to a line, used in sounding the depth of water; a plumb bob or a plumb line.
2. Hence, any weight.
3. A piece of lead formerly used by schoolchildren to rule paper for writing (that is, to mark with rules, with lines).
4. A violent or dramatic fall.
5. A decline; a fall; a drop.

1. To drop swiftly, in a direct manner; to fall quickly.

Etymology

From Middle English plommet (“ball of lead, plumb of a bob-line”), recorded since 1382, from Old French plommet or plomet, the diminutive of plom, plum (“lead, sounding lead”), from Latin plumbum (“lead”). The verb is first recorded in 1626, originally meaning “to fathom, take soundings", from the noun.