plumb line

American  

noun

1. a cord with a lead bob attached to one end, used to determine perpendicularity, the depth of water, etc.

2. plumb rule.

---

plumb line British  

noun

1. a string with a metal weight at one end that, when suspended, points directly towards the earth's centre of gravity and so is used to determine verticality, the depth of water, etc

2. another name for plumb rule

---

plumb line Scientific  

/ plŭm /

1. A line regarded as directed exactly toward the Earth's center of gravity.

---

Etymology

Origin of plumb line

First recorded in 1530–40

Example Sentences

"It's the lead weight from a plumb line."

From BBC

Drop a plumb line from the top of the head down through the spine into the heels in first position, divide the body down this center, right from left.

From New York Times

“When I took down the remaining wallpaper in preparation for new wallpaper, I came across all her notes, measurements and marks for plumb lines. It brought back so many memories.”

From Washington Post

The next day, they came back with a plumb line and a ruler to measure every distance between every component.

From Literature

If a factory was nearby, he’d explain how you used a plumb line to get the chimney straight and why the windows had been placed a certain way to let in the maximum light.

From Literature