Annotto \An*not"to\, Arnotto \Ar*not"to\, n. [Perh. the native name.] A red or yellowish-red dyeing material, prepared from the pulp surrounding the seeds of a tree ({Bixa orellana}) belonging to the tropical regions of America. It is used for coloring cheese, butter, etc. [Written also {Anatto}, {Anatta}, {Annatto}, {Annotta}, etc.] Arnotto \Ar*not"to\, n. Same as {Annotto}.