I want to fill in the wiki for candlelight, but I'm not sure if it's referring to the actual light emitted by the candle, or to a specific object holding the candle aloft.

I think it should refer to the light. We already have the tags candelabra and candlestand for the candle holders, although the former is less used and the latter has no wiki; also the real-world definition for 'candlestand' is a bit vague since it could also mean a candelabrum, a candlestick, which is a holder for a single candle, or something like this ... I digress though...

In agreement with @kiyah123 that candlelight is the light itself. Specifically, I feel like this tag is for settings where candles provide the majority of ambient light. This makes for dark scenes with amber-colored light radiating out from the candles themselves; post #900845, post #2214626, and post #2428401 illustrate this effect vividly enough, and it's especially dramatic in post #197364 and post #1215310. Candlelight should be analogous with monitor light in this respect.

There are also a lot of examples of this tag getting added anywhere candles happen to be lit regardless of the lighting, like post #1831345 and post #2579338. This feels to me like gross misuse of the tag, and hopefully a proper wiki page will help to curtail it.