A light carriage or chaise. Examples 1753–1821, N.E.D. Obs. in England, and quite or nearly so in the U.S.

1

1781.  There is a good chair road from Savannah.—Advt., Royal Georgia Gazette, Jan. 4.

2

1816.  Instead of a chaise, they [the Virginians] use a chair, which is is very light, but unsocial, as they are usually single.—Henry C. Knight (‘Arthur Singleton’), ‘Letters from the South and West,’ p. 64 (Boston, 1824).

3

1833.  Merchants and professional gentlemen were quite content to keep a one-horse chair.—Watson, ‘Historic Tales of Philadelphia,’ p. 131.

4