A mottled mixture of black, grey, and white. Usually used in reference to hair. Her salt-and-pepper hair gave our teacher a look of distinction and authority.
salt
n. a sailor. (Especially with old.) I’ve sailed a little, but you could hardly call me an old salt.
salt and pepper
1. n. a black and white police car. There is a salt and pepper around the corner waiting for speeders.
2. mod. interracial, including black and white. It was sort of a salt and pepper meeting, with representatives from all neighborhoods.