The term "gunship" is used in several contexts, all sharing the general idea of a light craft armed with heavy guns.
In the Navy

Navy

A navy is the branch of a nation's armed forces principally designated for naval and amphibious warfare; namely, lake- or ocean-borne combat operations and related functions...

, the term originally appeared in the mid-19th century as a less-common synonym for gunboat

Gunboat

A gunboat is a naval watercraft designed for the express purpose of carrying one or more guns to bombard coastal targets, as opposed to those military craft designed for naval warfare, or for ferrying troops or supplies.-History:...

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In fixed-wing aircraft

Fixed-wing aircraft

A fixed-wing aircraft is an aircraft capable of flight using wings that generate lift due to the vehicle's forward airspeed. Fixed-wing aircraft are distinct from rotary-wing aircraft in which wings rotate about a fixed mast and ornithopters in which lift is generated by flapping wings.A powered...

 category, a gunship is an aircraft having lateral

Lateral

Lateral may refer to:*Lateral , an anatomical direction*Lateral canal, a canal built beside another stream*Lateral consonant, an ℓ-like consonant in which air flows along the sides of the tongue...

ly-mounted heavy armaments (i.e. firing to the side) to attack ground or sea targets. Most often, a gunship attacks the target while circling over it, performing a constant pylon turn

Pylon turn

A pylon turn is a flight maneuver in which an aircraft banks into a circular turn, in such a way that an imaginary line perpendicular to aircraft's axis points to a fixed point on the ground...

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