What's the difference between a sofa and a settee here?

Little, as the words are used on Sellingantiques. 'Settee' appears in over a quarter of titles and usually attaches to a show-frame piece with exposed timber. 'Sofa' is the broader label, and 'couch' turns up occasionally. 'Love seat' appears once in the sample.

Which period do most of these come from?

The dated listings run from 1850 to 1930, and they cluster late. The 1900s account for the largest group, followed by Edwardian, the 1920s and the 1910s. The 1860s is the thinnest decade with any real presence, at six listings. Earlier pieces surface only as one-offs: two Georgian entries and a single eighteenth-century one.

Are French two seaters common in this category?

More common than you might expect. 'French' appears in around one title in six, bringing gilt, painted and caned salon frames in the Louis XV and Louis XVI styles. They arrive with their own vocabulary too: canapé, corbeille and bergère all show up as listing words.

What does reupholstery included mean in a title?

The dealer is selling the frame with the cost of recovering built into the price. Ten archive titles use the formula, sometimes in capitals. It's an archive habit rather than a current one, and a related title offers a salon settee for re-upholstery.

Do chesterfields turn up as two seaters?

Yes, but as a handful of titles among a few hundred. The fully upholstered English group covers chesterfields, leather country-house sofas and Howard-type frames. Small as it is, that group occupies the upper end of the range.

Which timbers are used for the frames?

Mahogany leads, appearing in nearly a fifth of titles, with walnut next. Both turn up carved, inlaid or plain. Oak, rosewood, satinwood, beech and fruitwood also appear, along with ebonised finishes and the gilt and painted surfaces of the French frames.