Fiber ring
= Fiber ring
{title2=$B\otimes_A\kappa(\mathfrak p)$}
= Fibre ring
{synonym}
For a <ring homomorphism> $A\to B$ and a prime $\mathfrak p\subset A$, the fiber <ring> at $\mathfrak p$ is
$$
B\otimes_A\kappa(\mathfrak p).
$$
Its <prime ideals> correspond to the primes of $B$ whose contraction is $\mathfrak p$.