Is it true that all insects have six legs?

Yes, all known insects have six legs. This characteristic is part of the definition of an insect. Insects belong to the class Insecta, which is the most diverse group of animals, with over a million described species. One of the defining characteristics of insects is that they have three body segments (head, thorax, and abdomen) and three pairs of jointed legs, totaling six legs. This is in contrast to other arthropods, such as spiders, which have two body segments (cephalothorax and abdomen) and four pairs of legs, totaling eight legs.