A lady's companion was a woman of genteel birth who acted as a paid companion for women of rank or wealth. The term was in use in the United Kingdom from at least the 18th century to the mid-20th century. It was related to the position of lady-in-waiting, which by the 19th century was only applied to the female retainers of female members of the royal family. Ladies-in-waiting were usually women from the most privileged backgrounds who took the position for the prestige of associating with royalty, or for the enhanced marriage prospects available to those who spent time at court, but lady's companions usually took up their occupation because they needed to earn a living. A companion is not to be confused with lady's maid, a female personal attendant roughly equivalent to a "gentleman's gentleman" or valet.
Like a governess, a lady's companion was not regarded as a servant, but nor was she really treated as an equal. Only women from a class background similar to or only a little below that of their employer would be considered for the position. Women took positions as companions if they had no other means of support, as until the late 19th century there were very few other ways in which an upper- or upper-middle-class woman could earn a living which did not result in a complete loss of her class status. (Employment as a governess, running a private girls' school and writing were virtually the only other such options; hence the formation of the Society for Promoting the Employment of Women in 1859.)
The companion's role was to spend her time with her employer, providing company and conversation, to help her to entertain guests and often to accompany her to social events. In return she would be given a room in the family's part of the house, rather than the servants' quarters; all of her meals would be provided, and she would eat with her employer; and she would be paid a small salary, which would be called an "allowance" – never "wages." She would not be expected to perform any domestic duties which her employer might not carry out herself, in other words little other than giving directions to servants, fancy sewing and pouring tea. Thus the role was not very different from that of an adult relation in respect of the lady of a household, except for the essential subservience resulting from financial dependency.