This is a glossary of algebraic geometry.
See also glossary of commutative algebra, glossary of classical algebraic geometry, and glossary of ring theory. For the number-theoretic applications, see glossary of arithmetic and Diophantine geometry.
For simplicity, a reference to the base scheme is often omitted; i.e., a scheme will be a scheme over some fixed base scheme S and a morphism an S-morphism.
From the preface to I.R. Shafarevich, Basic Algebraic Geometry.
Kollár, János, Chapter 1, "Book on Moduli of Surfaces".
As a consequence, a scheme is separated when the diagonal of within the scheme product of with itself is a closed immersion. Emphasizing the relative point of view, one might equivalently define a scheme to be separated if the unique morphism is separated.