spider

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

• noun Any of numerous arachnids of the order Araneae, having a body divided into a cephalothorax and an abdomen, eight legs, two chelicerae that bear venom glands, and two or more spinnerets that produce the silk used to make nests, cocoons, or webs for trapping insects.
• noun One that resembles a spider, as in appearance, character, or movement.
• noun A program that automatically retrieves webpages and follows the links on them to retrieve more webpages. Spiders are used by search engines to retrieve publicly accessible webpages for indexing, and they can also be used to check for links to webpages that no longer exist.
• noun A trivet.

from The Century Dictionary.

• noun An arthropod of the order Araneæ, Araneina, or Araneida (the old Linnean genus Aranea), of the class Arachnida, of which there are many families, hundreds of genera, and thousands of species, found all over the world.
• noun Some other arachnidan, resembling or mistaken for a spider; a spider-mite. See red-spider.
• noun A spider-crab; a sea-spider.
• noun A cooking-utensil having legs or feet to keep it from contact with the coals: named from a fancied resemblance to the insect—the ordinary frying-pan is, however, sometimes erroneously termed a spider.
• noun A trivet; a low tripod used to support a dish, or the like, in front of a fire.
• noun In machinery:
• noun A skeleton of radiating spokes, as a rag-wheel.
• noun The internal frame or skeleton of a gear-wheel, for instance, on which a cogged rim may be bolted, shrunk, or cast.
• noun The solid interior part of a piston, to which the packing is attached, and to whose axis the piston-rod is secured.
• noun Nautical, an iron outrigger to keep a block clear of the ship's side.
• noun In the English form of pyramid-pool billiards, a skeleton rest, or bridge, designed for certain exigencies.
• noun In archery, a prize for the best gold, awarded at the Grand National Archery meeting in England.

from the GNU version of the Collaborative International Dictionary of English.

• noun (Zoöl.) Any one of numerous species of arachnids comprising the order Araneina. Spiders have the mandibles converted into poison fangs, or falcers. The abdomen is large and not segmented, with two or three pairs of spinnerets near the end, by means of which they spin threads of silk to form cocoons, or nests, to protect their eggs and young. Many species spin also complex webs to entrap the insects upon which they prey. The eyes are usually eight in number (rarely six), and are situated on the back of the cephalothorax. See Illust. under araneina.
• noun (Zoöl.) Any one of various other arachnids resembling the true spiders, especially certain mites, as the red spider (see under Red).
• noun An iron pan with a long handle, used as a kitchen utensil in frying food. Originally, it had long legs, and was used over coals on the hearth.
• noun A trevet to support pans or pots over a fire.
• noun (Mach.) A skeleton, or frame, having radiating arms or members, often connected by crosspieces; as, a casting forming the hub and spokes to which the rim of a fly wheel or large gear is bolted; the body of a piston head; a frame for strengthening a core or mold for a casting, etc.
• noun (Zoöl.) Same as Solitary ant, under Solitary.
• noun (Zoöl.) any one of numerous species of maioid crabs having a more or less triangular body and ten long legs. Some of the species grow to great size, as the great Japanese spider crab (Macrocheira Kempferi), measuring sometimes more than fifteen feet across the legs when they are extended.
• noun (Zoöl.) any one of numerous species of parasitic dipterous insects of the family Hippoboscidæ. They are mostly destitute of wings, and live among the feathers of birds and the hair of bats. Called also bird tick, and bat tick.
• noun (Zoöl.) any one of several species of East Indian sunbirds of the genus Arachnothera.
• noun filaments of a spider's web crossing the field of vision in optical instruments; -- used for determining the exact position of objects and making delicate measurements. Fine wires, silk fibers, or lines on glass similarly placed, are called spider lines.
• noun (Zoöl.) Any one of numerous small mites injurious to plants.
• noun (Zoöl.) any one of numerous species of South American monkeys of the genus Ateles, having very long legs and a long prehensile tail.
• noun (Bot.) a European orchidaceous plant (Ophrys aranifera), having flowers which resemble spiders.
• noun (Zoöl.) any shell of the genus Pteroceras. See Pteroceras.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun Any of various eight-legged, predatory arthropods, of the order Araneae, most of which spin webs to catch prey.
• noun Internet A program which follows links on the World Wide Web in order to gather information.
• noun A float (drink) made by mixing ice-cream and a soda or fizzy drink (such as lemonade).
• noun slang A spindly person.
• noun slang A man who persistently approaches or accosts a woman in a public social setting, particularly in a bar.
• noun snooker, billiards A stick with a convex arch-shaped notched head used to support the cue when the cue ball is out of reach at normal extension; a bridge.
• noun cooking A cast-iron frying pan with three legs, once common in open hearth cookery. They were generally called spiders both in England and in America.
• noun A part of a crank, to which the chainrings are attached
• noun slang Heroin (street drug).
• noun music Part of a resonator instrument that transmits string vibrations from the bridge to a resonator cone at multiple points.
• verb Internet, of a computer program to follow links on the World Wide Web in order to gather information.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun a computer program that prowls the internet looking for publicly accessible resources that can be added to a database; the database can then be searched with a search engine
• noun a skillet made of cast iron
• noun predatory arachnid with eight legs, two poison fangs, two feelers, and usually two silk-spinning organs at the back end of the body; they spin silk to make cocoons for eggs or traps for prey