knot

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A compact intersection of interlaced material, such as cord, ribbon, or rope.
• noun A fastening made by tying together lengths of material, such as rope, in a prescribed way.
• noun A decorative bow of ribbon, fabric, or braid.
• noun A unifying bond, especially a marriage bond.
• noun A tight cluster of persons or things.
• noun A feeling of tightness.
• noun A complex problem.
• noun A hard place or lump, especially on a tree, at a point from which a stem or branch grows.
• noun The round, often darker cross section of such a lump as it appears on a piece of cut lumber.
• noun A protuberant growth or swelling in a tissue.
• noun Nautical A division on a log line used to measure the speed of a ship.
• noun A unit of speed, one nautical mile per hour, approximately 1.85 kilometers (1.15 statute miles) per hour.
• noun A distance of one nautical mile.
• noun Mathematics A closed loop that is embedded in three-dimensional space and that can be intertwined with or tangled in itself, but that cannot intersect itself.
• intransitive verb To tie in or fasten with a knot or knots.
• intransitive verb To snarl or entangle.
• intransitive verb To cause to form a knot or knots.
• intransitive verb To form a knot or knots.
• intransitive verb To become snarled or entangled.
• noun Either of two migratory sandpipers of the genus Calidris that breed in Arctic regions, especially the red knot.

from The Century Dictionary.

• noun In musical instruments of the lute, viol, and similar classes, same as rose 1, 15.
• To complicate or tie in a knot or knots; form a knot or knots in or on: as, to knot a cord or a handkerchief.
• To fasten or secure by a knot.
• Hence To entangle; perplex.
• To unite or knit closely.
• To remove the knots from, as a woven fabric, by pulling them out with small tweezers.
• To cover the knots of: a preliminary process in painting on wood, so that the knots shall not show through.
• To cover (metals, etc.) with knotting. See knotting, 3.
• To form knots or joints, as in plants.
• To knit knots for fringe; produce fancy work made by tying knots in cords. Compare knotting, knotwork, knotted-bar work.
• To gather in knots; unite as in a knot.
• To form flower-buds.
• noun The robin-snipe; the red-breasted or gray-backed sandpiper, Tringa canutus, a bird of the snipe family, Scolcpacidæ:
• noun The ring-plover, Ægialitis hiaticula, whose habits on the beach resemble those of the knot.
• noun An interlacement of parts of a cord, rope, or any flexible strip, formed by twisting the ends about each other, and then drawing tight the loops thus formed; also, a similar interlacing of two or more cords, threads, etc.: a bunch of threads or thread-like things entangled together.
• noun Specifically A piece of ribbon, lace, or the like folded or tied upon itself in some particular form, used as an ornamental adjunct to a costume, or to a sword, a cane, etc.: as, a knot of ribbon; a breast-knot; a shoulder-knot.
• noun Something resembling a knot in its complication, its protuberancy, or its rounded form.
• noun The hard, cross-grained mass of wood formed in a trunk at the insertion of a branch; particularly, the round, gnarly formation resulting from a branch being broken off and the tissues growing around its stump. This stump often decays, or falls out in cutting, leaving a knot-hole.
• noun A node in a stem, or any node-like expansion in a stem, pod, etc.
• noun An excrescence on a trunk or root; a gnarl or knur.
• noun A tuft, as of grass.
• noun A flower-bud.
• noun In lithol., a small concretion or aggregation of mineral matter, or imperfectly developed crystal, found occasionally in schistose rocks, appearing to be the result of contact metamorphism. Knots of this kind sometimes occur crowded together in large numbers, so as to give a knotty appearance to what otherwise would be a quite smooth slaty surface. Such slate is called knotted slate or schist (in German knotenschiefer). The knots are sometimes simply segregations of ferruginous material around a small fragment of the slate; sometimes more or less distinctly formed crystals, andalusite being the most common mineral thus occurring. This peculiar formation is well shown in the eastern Vosges and in the lake district of England.
• noun In mech., same as knote.
• noun In architecture, same as knob.
• noun In brush-making, a tuft of bristles ready to be fastened into a hole in the stock.
• noun In anatomy, a ganglion; a node; a plexus.