In view of my mention of genres yesterday, here's a list of the Romance Writers' of America definitions of the romance genres (thanks to Linda for pointing me in the right direction!)
First, a brief intro: "All romances have a central love story and an emotionally satisfying ending. Beyond that, however, romance novels can be set in any time or place, entertain any number of plot elements, or convey moods from light and humorous to dark and suspenseful. The genre of romance can be classified into various sub-genres depending on their setting and plot elements.
Those sub-genres include:
Contemporary Series Romance Series romance novels that focus primarily on the romantic relationship and typically set after 1945.
Contemporary Single Title Romance Romance novels which focus primarily on the romantic relationship, released as individual titles, not as part of a series and set after 1945Historical Romance Romance novels set in any time period prior to 1945, and taking place in any location
Inspirational Romance Romance novels in which religious or spiritual beliefs (in the context of any religion or spiritual belief system) are a major part of the romantic relationship.
Novels with Strong Romantic Elements A work of fiction in which a romance plays a significant part in the story, but other themes or elements take the plot beyond the traditional romance boundaries.
Paranormal Romance Romance novels in which the future, a fantasy world or paranormal happenings are an integral part of the plot.
Regency Romance Romance novels in which the majority of the story is set against the Regency period of the British Empire.
Romantic Suspense Romance novels in which suspense, mystery, or thriller elements constitute an integral part of the plot.
Young Adult Romance Novels with a strong romantic theme geared toward young adult readers.
The RNA covers the field but in a less specific manner:
"Romantic fiction is the cross-genre genre. In the UK it appears under a variety of publishers' labels including general fiction, women's fiction, historical, romantic comedy, chick lit, sagas - even spooky - as well as romance. These are among the UK's most commercially successful book categories.
It embraces Jilly Cooper's 900 pages as well as the 187 Harlequin Mills & Boon category romances which are published every month; multi-generational sagas and Regency romps; deeply serious meditations on life and flippant twenty-somethings' metropolitan shenanigans. The engine of romantic fiction is love and relationships. The bodywork is infinitely variable."