Definitions of the Different Heat Levels?

Please pardon the "newbie" question, but does anyone have a list or a link to an actual description of the different romance heat levels? Like, I know "sweet" means maybe kissing, and anything else happens "behind closed doors," and erotica or "romantica" is very explicit, but I'm not really sure what the divisions are between. Like, what's the difference between "sensual" and "spicy"? I'm trying to craft a query letter ( ) and someone suggested I should included what heat level it is.

Thanks!

So, my current WIP is probably right at the upper end of "sensual." I mean, there are only two love scenes (and a few interrupted love scenes, lol my poor MCs), but they are reasonably explicit. Still within the confines of romance rather than erotica, I think. I guess an editor would let me know if they thought I was at a different heat level.

Thanks, everyone! I'll keep that in mind, and try to remember to look over the online guidelines for different publishers prior to submitting.