Insects are usually placed in the class Insecta (see also Hexapoda). The body of a typical adult insect is divided into head, thorax (bearing the legs and wings), and abdomen. The class includes many familiar forms, such as flies, bees, wasps, moths, beetles, grasshoppers, and cockroaches. Insects are the most numerous animals in both numbers of individuals and of different kinds, with more than a million species in all habitats except the sea, and they are of enormous economic importance as pests and carriers of disease, and also as pollinators
early 17th century (originally denoting any small cold-blooded creature with a segmented body): from Latin (animal) insectum 'segmented (animal)' (translating Greek zōion entomon), from insecare 'cut up or into', from in- 'into' + secare 'to cut'