[2] The generic name "mesoplodon" comes from the Greek meso- (middle) - hopla (arms) - odon (teeth), and may be translated as 'armed with a tooth in the centre of the jaw'.

The spindle-shaped body has a small dorsal fin and short and narrow flippers.

The beak, which vary in length between species, blends with the small melon without a crease.

[3] Sexual dimorphism is poorly known, but the females tend to be the same size or larger than males at least in some species.

The lower jaw often forms a huge arch in some species, sometimes extending above the rostrum in a shape comparable to a playground slide.

The dorsal fin is rather small and located between two-thirds and three-quarters down the back of the animal.