The grasshopper is an insect

Insect

Insects are a class of living creatures within the arthropods that have a chitinous exoskeleton, a three-part body , three pairs of jointed legs, compound eyes, and two antennae...

 of the suborder Caelifera in the order Orthoptera

Orthoptera

Orthoptera is an order of insects with paurometabolous or incomplete metamorphosis, including the grasshoppers, crickets and locusts.Many insects in this order produce sound by rubbing their wings against each other or their legs, the wings or legs containing rows of corrugated bumps...

. To distinguish it from bush crickets or katydids

Tettigoniidae

The family Tettigoniidae, known in American English as katydids and in British English as bush-crickets, contains more than 6,400 species. It is part of the suborder Ensifera and the only family in the superfamily Tettigonioidea. They are also known as long-horned grasshoppers, although they are...

, it is sometimes referred to as the short-horned grasshopper. Species that change colour and behaviour at high population densities are called locust

Locust

Locusts are the swarming phase of short-horned grasshoppers of the family Acrididae. These are species that can breed rapidly under suitable conditions and subsequently become gregarious and migratory...

s.
Grasshoppers have antennae

Antenna (biology)

Antennae in biology have historically been paired appendages used for sensing in arthropods. More recently, the term has also been applied to cilium structures present in most cell types of eukaryotes....

 that are generally shorter than their body and short ovipositor

Ovipositor

The ovipositor is an organ used by some animals for oviposition, i.e., the laying of eggs. It consists of a maximum of three pairs of appendages formed to transmit the egg, to prepare a place for it, and to place it properly...

s. They also have pinchers or mandibles

Mandible (insect)

Insect mandibles are a pair of appendages near the insect’s mouth, and the most anterior of the three pairs of oral appendages . Their function is typically to grasp, crush, or cut the insect’s food, or to defend against predators or rivals...

 that cut and tear off food.