Biracial, Multiracial... what?

Technically and biologically speaking, if your mum is Black-American and does have hints of White in her genetic makeup, and you have an Arab father, you would be multiracial because you would be comprised of multiple races that number at more than two, which are Sub-Sahara African Black, White, and Arab. However, in the social sense, which mainly regard filling out forms that require race, the "one-drop rule," etc., you would probably be considered biracial because, if your mum has hints of White ancestry from "way back" rather than having a White parent, she would still be considered a non-mixed Black-American. Thus, your racial makeup, socially speaking, would be Black-American and Arab, which are two races, and therefore "bi."