Answers:

C47: a wooden clothespin used to attach a color correction gel or diffusion to the barn doors on a light. The name "C47" may have come from an attempt to make it sound less mundane than a clothes-pin, or it may have come from the label on the bin used to store them in an early studio.[3] More commonly believed is that the name "C47" came to be the designation that the clothes-pins were given when printed on studio budgets to trick budget managers into approving the request for them. A "C74" or "74C" is a clothes-pin that has been taken apart, reversed, and put back together so that the small end comes together.
http://en.wikipedia.org/wiki/Clothespin

Apple Box: The term apple box, or apple crate, is used in the production of film or photography to indicate a mobile box or platform sturdy enough to support weight. The generally accepted dimensions for an apple box are 12" × 8" × 20", though they may vary by three to five inches in any direction. Any insignificant deviation in size does not disclude an object from being an apple box, though significantly smaller or larger items may be termed a "half-apple," "quarter-apple" or sometimes "double apple." An "eighth-apple" is sometimes called a pancake or a lift.
The very first apple boxes were simple crates used in apple orchards, the modern variety should not be confused with the crates used in modern orchards as they vary in size up to a four-foot cube.
http://en.wikipedia.org/wiki/Apple_box

Grip: In the USA, a grip is a skilled person responsible for the set up, adjustment and maintenance of production equipment on the set. Their typical duties involve camera movement, lighting refinement, and mechanical rigging. imdb: http://www.imdb.com/Glossary/G

Walkie: a two way radio

Prime Lens: A prime lens is a mechanical assembly of lenses whose focal length is fixed, as opposed to a zoom lens, which has a variable focal length. Prime lenses are not as versatile as their zoom counterparts, but are often of superior optical quality and lower cost. This is because the designs are simpler (fewer moving parts), and can be optimized for one particular focal length, whereas zoom lenses must function at a variety of focal lengths. wikipedia: http://www.google.com/url?sa=X&start=0&oi=define&q=http://en.wikipedia.org/wiki/Prime_lens

C-Stand: Short for a Century Stand, made by Matthews, and other grip companies, to hold just about anything off the ground. Used often for lights and scrims.

Scrim: Lighting attachment which, when placed in front of a lamp, reduces its strength, usually by one stop, without affecting lighting quality or color.
www.startphoto.com/learn/glossary/glossary_s-sh.htm

Mag: short for the magazine that houses the film

Kino: Short for Kino Flo or Fluorescent Daylight and Tungsten Balanced Light.

HMI: In film prodcution, a HMI is a light. HMI stands for Hydragyrum Medium Iodide.

Fresnel: The lens invented by Augustin Fresnel in 1821 which consists of concentric ridges radiating outward from the central lens (bullseye), with prisms positioned at the top and bottom of the ridges to refract the light from the light source placed behind the central lens. A term normally used only when referring to traditional cut glass style lenses, although the Fresnel principle is also found in more modern glass or plastic lenses.
www.nslps.com/r&p_glossary_of_terms.asp

First Assistant Camera: AKA: 1AC; AKA: focus puller; AKA: B Cameraman; A member of the camera crew who adjusts the focus of the camera during filming. See also assistant cameraman. http://www.imdb.com/Glossary/F#focus_puller

Taco cart: a cart filled with lighting equipment including: lights, stands, clamps