Definition of "compounding"

Arthur Pendennis, his son, was eight years old at the time of this event, so that it is no wonder that the latter, who left Bath and the surgery so young, should forget the existence of such a place almost entirely, and that his father’s hands had ever been dirtied by the compounding of odious pills, or the preparation of filthy plasters

1848 November – 1850 December, William Makepeace Thackeray, chapter 2, in The History of Pendennis. […], volumes (please specify |volume=I or II), London: Bradbury and Evans, […], published 1849–1850