Lord is an appellation for a person or deity who has authority, control, or power over others, acting as a master, chief, or ruler. The appellation can also denote certain persons who hold a title of the peerage in the United Kingdom, or are entitled to courtesy titles. The collective "Lords" can refer to a group or body of peers.

Lady is a term for a woman who behaves in a polite way. Once used to describe only women of a high social class or status, the female counterpart of lord, now it may refer to any adult woman, as gentleman can be used for men. Informal use is sometimes euphemistic.