a key that changes or extends the meaning of a keyboard key. Examples of modifier keys are Shift, Ctrl, and alt.

the main industrial standardization organization in the United States. There are official ANSI standards in almost all industries, and many of them have to do with computers. In computer programming, ANSI most often refers to one of the following:

1. ANSI standard versions of C, FORTRAN, COBOL, or other programming languages. Typically, a particular manufacturer's version of a language will include all of the features defined in the ANSI standard, plus additional features devised by the manufacturer. To be easily transportable from one computer to another, a program should not use any features that are not in theANSI standard. The programmer can then produce executable versions of it for different types of computers by compiling the same program with different compilers.
2. ANSI standard escape sequences for controlling the screen of a computer terminal or microcomputer. An escape sequence is a series of character codes which, when sent to the screen, causes the screen to do something other than simply display the characters to which the codes correspond. The ANSI escape sequences all begin with theASCII Escape character (code 27). See ANSI screen control.
3. The ANSI extended character set used in MicrosoftWindows, and shown in Table 2. It includes all the ASCII characters plus many others. See ASCII ; IBM PC; Unicode; Windows (Microsoft).

To type any ANSI character in Microsoft Windows, hold down the Alt key while typing 0 followed by the character code number on the numeric keypad at the right-hand side of the keyboard. For example, to type é, hold down Alt and type 0233. You may prefer to use the Character Map utility to select characters and copy them to the Clipboard, and then paste them into your application.

computer term. The code converts a character into a binary number used by most microcomputers and information services (on-line data bases) so that different makes of microcomputers may be able to communicate with each other. ASCII is used on most microcomputers, computer terminals, and printers. ASCII codes also include control characters that information services use. Many computer books and some software programs (e.g., Borland International's Sidekick) have a table of ASCII characters. The use of ASCII also allows for data files generated by one type of program (i.e., data base management system) to be used in another type of program (i.e., spreadsheet). An example of an ASCII application follows. Data may be downloaded from an information service (e.g., Dow Jones News/Retrieval) in ASCII and then loaded into a word processing program and edited and printed out or even sent to another computer using a telecommunications program. ASCII is quite helpful in electronic mail because with MCI, for example, the accountant can upload an ASCII file as electronic mail to his clients.