The Oort cloud is a cloud of predominantly icy planetesimals believed to surround the Sun to as far as somewhere between 50,000 and 200,000 Astronomical Units (0.8 and 3.2 Light Years).
An interstellar comet is a comet (or exocomet) located in interstellar space, and not gravitationally bound to a star.
Bow shocks form the boundary between a magnetosphere and an ambient magnetized medium. This occurs when the magnetic field of an astrophysical object interacts with the nearby flowing ambient plasma.
Photoevaporation denotes the process where energetic radiation ionises gas and causes it to disperse away from the ionising source. This typically refers to an astrophysical context where ultraviolet radiation from hot stars acts on clouds of material such as molecular clouds, protoplanetary disks, or planetary atmospheres.
The habitable zone (HZ), is the range of orbits around a star within which rocky planets with sufficient atmospheric pressure can support liquid water at their surfaces.