A chair with elbows: see ELBOW sb. 3.

1

a. 1704.  T. Brown, Praise Drunk., Wks. 1730, I. 36. A Drunkard seated in an elbow chair, majestically spewing.

2

1822.  W. Irving, Braceb. Hall, ii. 9. Very eloquent in praise of an ancient elbow chair.

3