An ebit is one unit of bipartite entanglement, the amount of entanglement that is contained in a maximally entangled two-qubit state (Bell state).

If a state is said to have X ebits of entanglement (quantified by some entanglement measure) it has the same amount of entanglement (in that measure) as X Bell states. If a task requires Y ebits, it can be done with Y or more Bell states, but not with fewer.

Maximally entangled states in d × d dimensions have log2(d) ebits.