Fill light - Fill is used to lighten shadows and control Contrast and Lighting Ratios

Key light(main light)- may determine the character of the lighting like the mood 

Hair light - limited to the top of the head background light.

Shadowless- every angle is evenly light. 

Hard light - A relatively small, direct, usually focusable source, with or without lens, that produces strong High-lights and dark shadows.

Soft light- Diffused, Bounced, indirect light; the opposite of Hard Light.

Grey card-reflectance card used instead of a subject for a Reflected Light Meter reading.

Reflector- Variously shaped "bowls"  that shape and intensify a lamp's Beam.

Diffuser- A Translucent material placed in front of a Light to soften Highlights and Shadows, reduce Contrast and increase Beam Angle.

Intensity- The "strength" of the Incident Light.

Background light-Reveals the character of the background and helps separate it from the subject.