A key light is the main source of light in a video or photo. High-key lighting results in brightly lit subjects with more fill light and softer shadows. Fill lights are used to increase the amount of ambient light in a scene and reduce the contrast. 

A fill light is a style of lighting which is often used in theatre and film as well as in photography. Often used as part of a three point lighting set up, fill lighting is utilised in order to light up the shadowed parts of your setting - this creates less contrast where you do not want it. 

A soft box is a type of photographic lighting modifier, one of a number of photographic soft light devices. All the various soft light types create even and diffused light by transmitting light through some scattering material, or by reflecting light off a second surface to diffuse the light. 

A reflector is a photography tool used to redirect light to a subject or scene. It doesn't create light; rather, it redirects light that is already there. A reflector is good for creating fill light or lessening shadows.

In definition, a remote shutter release is, as the term implies, a remote trigger that can be connected to your camera either wirelessly or by using a cable to perform its main function: to release the shutter even remotely without physically touching your camera's built-in shutter release button. 

A catch light is the light reflected in a subject's eye, the glimmer that comes from an external light source. Also known as an "eye light," it's the highlight reflected off the surface of the eye.