KNOT definition

From ;. Cognate with Dutch knot.

A looping of a piece of string or of any other long, flexible material that cannot be untangled without passing one or both ends of the material through its loops.

Climbers must make sure that all knots are both secure and of types that will not weaken the rope.
A tangled clump.

The nurse was brushing knots from the protesting child's hair.
A maze-like pattern.
A closed curve that is an abstraction of a knot (in sense 1 above).
A difficult situation.

I got into a knot when I inadvertently insulted the policeman.
A unit of speed, equal to one nautical mile per hour.

Cedric claimed his beat-up old yacht could make 20 knots, if he would just make a few repairs, but we figured he was pulling our leg.
Either of two species of small wading birds, the red knot (Calidris canutus) and the great knot (Calidris tenuirostris).
The whorl left in lumber by the base of a branch growing out of the tree's trunk.

When preparing to tell stories at a campfire, I like to set aside a pile of pine logs with lots of knots, since they burn brighter and make dramatic pops and cracks.
Local swelling in a tissue area, especially skin, often due to injury.

Jeremy had a knot on his head where he had bumped it on the bedframe.
A group of people or things.
- 1968, Bryce Walton, Harpoon Gunner, Thomas Y. Crowell Company, NY, (1968), page 20,
  
  He pushed through knots of whalemen grouped with their families and friends, and surrounded by piles of luggage.

To form into a knot; tie with (a) knot(s).

We knotted the ends of the rope to keep it from unravelling.
To form wrinkles in the forehead, as a sign of concentration, concern, surprise, etc.

She knotted her brow in concentration while attempting to unravel the tangled strands.