Reserved word
A reserved word may refer to any of the following:
1. Often found in programming languages and macros, reserved words are terms or phrases appropriated for special use that may not be utilized in the creation of variable names. For example, "print" is a reserved word because it is a function in many languages to show text on the screen.
2. Reserved words are used in operating systems as a method of identifying a device file or another service. Below is a listing of Microsoft reserved words in MS-DOS and Windows operating systems. When attempting to use any of the following reserved words as a file name or command, you may receive an error message. For example, attempting to save a file as CON or CON.txt may generate a reserved file name or access denied error or say the file already exists.
| Reserved Word | What it is |
|---|---|
| AUX | Auxiliary port, aka Serial Port COM1. |
| CON | Console, which Microsoft describes as the display monitor or keyboard. |
| COM1 | COM port |
| COM2 | COM port |
| COM3 | COM port |
| COM4 | COM port |
| LPT1 | LPT port |
| LPT2 | LPT port |
| LPT3 | LPT port. |
| NUL | NULL |
| PRN | Printer aka LPT1 |
Device file, Java reserved words, Operating system terms, Programming terms, Reserved character, Word