- any animal of the class Insecta, comprising small, air-breathing arthropods having the body divided into three parts (head, thorax, and abdomen), and having three pairs of legs and usually two pairs of wings.
- any small arthropod, such as a spider, tick, or centipede, having a superficial, general similarity to the insects.Compare arachnid.
- a contemptible or unimportant person.
- of, pertaining to, like, or used for or against insects: an insect bite; insect powder.
- any small air-breathing arthropod of the class Insecta, having a body divided into head, thorax, and abdomen, three pairs of legs, and (in most species) two pairs of wings. Insects comprise about five sixths of all known animal species, with a total of over one million named speciesRelated adjective: entomic
- (loosely) any similar invertebrate, such as a spider, tick, or centipede
- a contemptible, loathsome, or insignificant person
c.1600, from Latin (animal) insectum “(animal) with a notched or divided body,” literally “cut into,” from neuter past participle of insectare “to cut into, to cut up,” from in- “into” (see in- (2)) + secare “to cut” (see section (n.)). Pliny’s loan-translation of Greek entomon “insect” (see entomology), which was Aristotle’s term for this class of life, in reference to their “notched” bodies.
First in English in 1601 in Holland’s translation of Pliny. Translations of Aristotle’s term also form the usual word for “insect” in Welsh (trychfil, from trychu “cut” + mil “animal”), Serbo-Croatian (zareznik, from rezati “cut”), Russian (nasekomoe, from sekat “cut”), etc.
- Any of numerous usually small arthropod animals of the class Insecta, having an adult stage characterized by three pairs of legs and a body segmented into head, thorax, and abdomen and usually having two pairs of wings.
- Any of various similar arthropod animals, such as spiders, centipedes, or ticks.
- Any of very numerous, mostly small arthropods of the class Insecta, having six segmented legs in the adult stage and a body divided into three parts (the head, thorax, and abdomen). The head has a pair of antennae and the thorax usually has one or two pairs of wings. Most insects undergo substantial change in form during development from the young to the adult stage. More than 800,000 species are known, most of them beetles. Other insects include flies, bees, ants, grasshoppers, butterflies, cockroaches, aphids, and silverfish. See Notes at biomass bug entomology.