spotter

A person who observes something.

A member of a sniper team who in addition to this function is responsible for providing additional information about targets from a different point of view.

One who supervises a person performing an activity, in order to help them should they be unable to complete it.

Due to a spotter's lack of action in holding the weight when a lifter lost her balance, the lifter badly pulled some muscles.

A person who gives directions for a crane or vehicle (that is challenging to navigate) from a different point of view to the moved load.

Dolphins of the genus Stenella, and specifically Stenella attenuata distinguished from the streaker (Stenella coeruleoalba) and the spinner (Stenella longirostris).