The basics, from a to b...
(1) Method of cooking using radiant heat. If this doesn't mean anything to you, then think of a hot dog on a stick over an open flame. Sound familiar now? (Better, eh?)
(2) Since ultralight stoves are so small, and ultralight backpackers so frugal about carrying more than a few drops of fuel, they don't have much use for roasting, although it could be an option if you find a good supply of small, edible bugs some day. Other than that, roasting is really the basic idea behind a full-coverage wind screen, which allows complete use of a stove's heat output by protecting the stove and pot from wind, and bouncing the heat around inside the wind screen as much as possible before finally letting it escape through the very smallest of chimney holes at the top. (It works!)
(3) Cooking by dry heat, usually in an oven, but possibly over or near an open flame or other heat source. Roasting causes caramelizing or "Maillard browning" of the food's surface, which enhances flavor. (Also true. Everything here is true.)
Refs:
Improve Me Once Already! (Alcohol Stove Version)
Super Duper Ultralight Windscreen
Have anything worth adding? Then try sosayseff+eff@gmail.com
Me? Recently reaffirmed that roasting does not make my fingers feel better.
Etc...
so says eff: sporadic spurts of grade eff distraction
definitions: outdoor terms
fiyh: dave's little guide to ultralight backpacking stoves
boyb: dave's little guide to backpacks
snorpy bits: nibbling away at your sanity
last seen receding: missives from a certain mobile homer
noseyjoe: purposefully poking my proboscis into technicals