| Subject | Spanish | English |
| comp., MS | clave NULL | null key (A null value that is encountered in a key column) |
| comp., MS | objeto null | null object (An object with no members) |
| comp., MS | parámetro que no admite valores NULL | nonnullable parameter (A parameter which cannot take a NULL value) |
| comp., MS | propiedad que admite valores NULL | nullable property (A property which controls if a field can have a NULL value) |
| comp., MS | tipo que acepta valores NULL | nullable type (In C, an instance of the System.Nullable struct that can represent the normal range of values for its underlying value type, plus an additional null value) |