plumb-, plumbo-, plumbi- +

1. A reference to, or containing, lead; used specifically to designate those compounds in which it has a lower valence as contrasted with plumbic (high valence) compounds.
2. Relating to or consisting of lead.

1. The technical name of lead.
2. The metallic element lead.

1. The metal bob of a plumb line.
2. To drop sharply, steeply, and suddenly downward; especially, from a very high place: "The acrobat slipped and quickly plummeted into the net."

"The car swerved and plummeted to the bottom of deep canyon."

3. To fall straight down; to plunge.
4. To decline suddenly and steeply: "The weather forecaster said the temperatures would plummet tomorrow."
5. To experience a sudden unexpected decrease in something; such as, value or price: "He noticed that his stock prices plummeted in value after the bad economic news."
6. To suddenly become pessimistic or to decline suddenly; especially, from a state of optimism to one of pessimism.
7. Etymology: from plumb which came from Latin plumbum, "lead" via Old French plombe.

1. To thrust into water, or into any substance that is penetrable; to immerse; to cause to penetrate or enter quickly and forcibly; to thrust; as, to plunge the body into water; to plunge a dagger into the breast. Also used figuratively; as, to plunge a nation into war.
2. The act of thrusting into or submerging; a dive, leap, rush, or pitch into, or as into, water; such as, to take the water with a plunge.
3. Desperate hazard or act; a state of being submerged or overwhelmed with difficulties.
4. The act of pitching or throwing one's self headlong or violently forward, like an unruly horse.
5. Heavy and reckless betting in horse racing; hazardous speculation.
6. A plunge bath, an immersion by plunging; also, a large bath in which the bather can wholly immerse himself or herself.
7. Etymology: Plunge came into English from Old French plungier (c.1140), from Vulgar Latin plumbicare, "to heave the lead", from Latin plumbum, "lead". The original notion perhaps is of a sounding lead or a fishing net weighted with lead. Figurative use as in "to take the plunge" or "to commit oneself" is from 1845. A plunger as a mechanism is from 1777. "Plunging neckline" is attested from 1949.

1. A hand tool consisting of a long handle with a rubber suction cup at one end; used to clean clogged drains; AKA "a plumber's helper".
2. A mechanical device that has a plunging or thrusting motion.
3. Someone who dives into water.
4. Anyone who risks losses for the possibility of bigger gains.
5. Anyone who gambles frequently and recklessly.
6. A machine part; such as, a piston, that operates with a thrusting or plunging movement.