By actual lights, I mean umbrella & back lights... I shoot with a canon 1000D...will be shooting indoors with a backdrop...i've always prefered natural light, but wanted to give lights a try... For now, I use my built in flash and add flash fill on edit if needed....
An umbrella is only a modifier. Back lights can be speedlights, monolights, pack and head lights, hot lights, incandescent lights, flourescent lights, the sun, a window, or whatever.
Lights - Sources that emit photons.
Flashes - (in relation to photography) light sources than emit a quick pulse of light. (interchangable with strobe)
Strobes - light sources than emit a quick pulse of light. (interchangable with flash)
Speed light / speed lite / hot shoe flash - Small flash that sits in a camera's hot shoe and will fire when triggered by the camera. Can be fired off camera like a more portable version of a monolight or pack and head system. Generally provide much less power that the afore mentioned types of light.
Mono light - flash that is generally larger and heavier with the power source build into the same housing at the bulbs.
Pack and head system - a system that consist of a power pack that is separate from the flash housing and connects via cables. Heads share overall power of the pack and are generally only adjustable in certain increments and ratios.
Continuous light - a light source that emits a continuous light. A light bulb is a continuous source. Generally requires much more power to provide anywhere near as much power as a flash/strobe.
Modifiers - objects that modify the shape, color, or quality of a light source. These can be umbrellas, soft boxes, grids, snoots, gels, colored bottles, tissues paper, carboard boxes, etc..