Either

Note that in academic, as in ordinary, English the choices offered by either and or are thought of as exclusive. The native English speaker does not need to add but not both. It is understood. Indeed, if the choices are not exclusive, the native speaker feels impelled to add or both. In Boolean logic, as used in computer programming, there are two forms of or [OR and XOR] to make this so clear and simple that even a computer can 'understand' it. See also and/or.

For the pronunciation, see Either - neither.