What does annotto or arnotto mean?
The definition of annotto and arnotto
An*not”to, Ar*not”to, n.
Etym: [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.]