What is a yoke? Is that a stirrup?
If they're different, is the stirrup that U-shaped thing that you mount to the stand?
What is a spigot?

A yoke is the U shaped bracket on a lamp that mounts it on top a stand that has a spigot on the end of it to clamp onto!

http://en.wikipedia.org/wiki/Stage_lighting_instrument

You can also get double ended spigots that can be used with clamps to fix lights: http://www.doughty-engineering.co.uk/cgi-bin/trolleyed_public.cgi?action=showprod_T73900

I would imagine a stirrup is the same as a yoke.

So the stirrup is a yoke. Thanks, wanted to clarify that.

So the spigot is the piece on the end of a stand that the light sits on?

http://i01.i.aliimg.com/photo/v0/227479655/floor_stand_light_stand_with_spigot.jpg

^ the uppermost metal-looking part. that's a spigot?

One of my lights came with a little thing that once you put the light's yoke/stirrup onto that little piece that I pointed out above, it goes over the top of it and then you tighten it down with a grip head. I was thinking that the little locking clamp piece was actually a spigot.

Hey Gary,

What you call a spigot out here on the west coast of the USA I believe is called a spud. Always interesting to learn about different terminology.

-Garrett

Well here in the UK a spud is what you make fries with! ;0)

http://ilovespud.com/