A pendant picture is one of two pictures designed to hang together as a matching pair.
Pendant means hanging, and the term seems to originate in the idea of one hanging from the other – i.e. attached to the other. In practice pendant pairs of pictures were usually displayed on either side of a fireplace, or even a door. They are usually the same size and of subjects that are basically similar but differ in detail. Pendant pairs are often husband and wife portraits.
Pendant pairs were not always conceived as such – buyers of a one-off picture would sometimes ask the artist to paint a pendant.