Technically, ebonics is a 'cant'. It is neither a regional accent, in which the same words are used, but pronounced differently, nor is it a dialect, which substitutes specific words but keeps the word order of the language as it is spoken. Ebonics uses English words, but it is not English. For that reason, it is also not a patois, a creole, or a pidgin. It is not an independent language of its own, so it is not a language.
A 'cant' is crypto-dialect of a group, intentionally designed to communicate amongst members of the group while discouraging understanding by those outside the group. It is an extreme form of slang, which all children use. It is most similar to Polari from the UK, derived from English and Romany and used by, of all things, a homosexual subculture there.