What's the difference between a credenza and a sideboard?

Very little, in how these are titled. Sideboard is the commonest word on Sellingantiques, in 598 titles, and credenza tends to be used for the shaped, cupboard-fronted Victorian side cabinet made for the drawing room as much as the dining room. Many dealers use both words in one title, along with side cabinet or chiffonier. Reading the timber, shaping and date in the description tells you more than the noun does.

Which wood is most common?

Walnut, in 527 titles, with burr walnut in 298 of those. Mahogany follows at 343, then oak at 158, rosewood at 75 and pine at 35. Rosewood shows up largely on chiffoniers, oak and pine on dresser bases, and mahogany on the Georgian and Regency sideboards.

How old are most of these?

The dated field spans 1700 to 1940, but more than half the dating is a period band rather than a year. Victorian appears as a label on 292 listings, 19th Century on 250. Where a decade is given, the 1860s lead with 143 listings and the 1850s follow with 89, then the 1880s and 1870s. The 1800s account for the Georgian and Regency end.

Do credenzas usually have marble tops?

No. Marble appears in 67 titles out of the whole archive, and marble top in 54. Mirror backs are scarcer still, in 34 titles. The plain wooden serving top is the norm.

Are these often found in pairs?

Occasionally. Paired walnut credenzas, rosewood cabinets and painted Swedish enfilades all turn up, which is unusual in a form generally made singly. Single pieces are what you'll meet most of the time.

What unusual examples turn up in this category?

One-offs surface now and then: a Hungarian carved dresser base, an aluminium Art Deco aviator sideboard, a Scottish dairy dresser, an Irish cedar two-door cupboard, a child-sized ebonised credenza. At the top end sit French ormolu- and porcelain-mounted commodes and an exhibition-scale carved mahogany mirror-back console. None of these represent the category, but the heading is wide enough to hold them.