plummets

A piece of lead attached to a line, used in sounding the depth of water, a plumb bob or a plumb line

Hence, any weight

A piece of lead formerly used by school children to rule paper for writing (that is, to mark with rules, with lines)

A plummet line, a line with a plummet; a sounding line

Violent or dramatic fall

A decline; a fall; a drop

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

“After its ascent, the arrow plummeted to earth.”