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 of hair or similar.

The nurse was brushing knots from the protesting child's hair.

A maze-like pattern.

A non-self-intersecting closed curve in (e.g., three-dimensional) space that is an abstraction of a knot (in sense 1 above).

A knot can be defined as a non-self-intersecting broken line whose endpoints coincide: when such a knot is constrained to lie in a plane, then it is simply a polygon.

A difficult situation.

I got into a knot when I inadvertently insulted a policeman.

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 tightened and contracted part of a muscle that feels like a hard lump under the skin.

A protuberant joint in a plant.

Any knob, lump, swelling, or protuberance.

The swelling of the bulbus glandis in members of the dog family, Canidae.

The point on which the action of a story depends; the gist of a matter.

the knot of the tale

A node (point at which the lines of a funicular machine meet from different angular directions)

A kind of epaulet; a shoulder knot.

A group of people or things.

A bond of union; a connection; a tie.

A unit of speed, equal to one nautical mile per hour.

Cedric claimed his old yacht could make 12 knots.

A unit of indicated airspeed, calibrated airspeed, or equivalent airspeed, which varies in its relation to the unit of speed so as to compensate for the effects of different ambient atmospheric conditions on aircraft performance.

In the early stages of reentry, due to the extremely-rarefied air at these altitudes, the space shuttle flew at only one to a few knots equivalent airspeed, even when its actual speed was many thousands of knots.

A nautical mile.

The bulbus glandis.

A group of snakes, intertwined.

To form into a knot; to tie with a knot or knots.

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.

To unite closely; to knit together.

To entangle or perplex; to puzzle.

To form knots.

To knit knots for a fringe.

One of a variety of shore birds; red-breasted sandpiper (variously Calidris canutus or Tringa canutus).