A chicken is a domesticated bird that is raised on farms for meat or eggs. Many cities allow people to keep a few chickens in their yards as pets and egg layers.
You can talk about your pet chicken with its brown feathers and funny feet, but you might also use the word chicken to order dinner at a restaurant: "I'll have the chicken." When a person is described as a chicken, it means she's easily scared or a coward. The Old English cicen, "young fowl," is the source of chicken. Calling someone chicken for being frightened has been hurting feelings since the 14th century.