According to Wikipedia, insects belong to "the most diverse groups of animals on the planet, including more than a million described species." Most of these species are insects. Other species of the Arthropoda phylum include crabs and lobsters. read more
Insects are classified as animals. ‘Insect’ is a class in the phylum of ‘Arthropoda’. Arthropods are in the subkingdom metazoan. ‘Metazoa’ are in the kingdom af ‘animal’. Further, Arthropoda are metazoans. thus, they are deeply nested in the kingdom ‘animal’. Arthropod have the four tissue types common to all metazoans. read more
Answer . Anything that has six legs and an exoskeleton, I believe, is an insect.. Insect is just a fancy term for critter or bug. read more