monochrome

Short definition from Wiktionary

Noun

1. 1
   A black and white image, especially such a photograph.
2. 2
   A painting executed in shades of a single colour.
3. 3
   A ceramic glaze of a single colour; an object so glazed.

Adjective

1. 1
   Having only one colour.
2. 2
   Representing colours with shades of gray.