Real Dictionary

knot
A knot of people is a group of people who are standing very close together.
countable noun: If you feel a knot in your stomach, you get an uncomfortable tight feeling in your stomach, usually because you are afraid or excited.
countable noun: If you tie a knot in a piece of string, rope, cloth, or other material, you pass one end or part of it through a loop and pull it tight.
verb: If you knot a piece of string, rope, cloth, or other material, you pass one end or part of it through a loop and pull it tight.

knot in American English 1
a lump or knob in a thread, cord, etc., formed by passing one free end through a loop and drawing it tight, or by a tangle drawn tight
noun: an interlacing, twining, looping, etc., of a cord, rope, or the like, drawn tight into a knob or lump, for fastening, binding, or connecting two cords together or a cord to something else

knot in American English 2
any of various sandpipers (genus Calidris); esp., a large, migratory species (C. canutus) that breeds in arctic regions
noun: either of two large sandpipers, Calidris canutus or C. tenuirostris, that breed in the Arctic and winter in the Southern Hemisphere

knot in British English 1
noun: any of various fastenings formed by looping and tying a piece of rope, cord, etc, in upon itself, to another piece of rope, or to another object

knot in British English 2
noun: a small northern sandpiper, Calidris canutus, with a short bill and grey plumage