bit 1. (b). Short for binary digit. The smallest unit of information a computer can hold. The value of a bit is 1 or 0. 2. Top-level newsgroup category for a BITNET mailing list newsgroup.

bit depth In bitmap graphics, the number of bits per pixel; the idea of bit depth can also be applied in storing other kinds of information. The number of bits per pixel determines the number of shades of gray or variations of color that can be displayed by a computer monitor. For example, a monitor with a bit depth of 1 can display only black and white; a monitor with a bit depth of 16 can display 65,536 different colors; a monitor with a bit depth of 24 can display 16,777,216 colors.

See 4-bit color, 8-bit color, 15-bit color, 16-bit color, 24-bit color, 32-bit color.

Bit Error Rate (BER). In fiber optics, the ratio of the number of bits received incorrectly to the number of bits transmitted.

bit level device A device whose input and output are in the form of data bits. Contrast pulse level device.

bit manipulation Low-level programming that works with individual bits.

bit rate The speed at which bits are transmitted, in bits per second. Also called data rate.

bit-oriented protocol A communications protocol in which the control codes are individual bits rather than bytes.

bitmap An image or other collection of data represented as an array of bits. In bitmap graphics, an image is displayed on the screen as a collection of tiny squares called pixels, which together form a pattern. Each pixel in the image corresponds with one or more bits; the number of bits per pixel determines how many shades of gray or colors can be displayed. "Bitmap" is used to refer to both the image itself and the file that holds the data for the image.

See bitmapped font, bitmap display, bitmap graphics, bit depth.

bitmap display A computer display in which each pixel onscreen is mapped to one or more bits in memory. Images are generated on the screen as the bit pattern to be displayed is written into video memory. Most current personal computers have bitmap displays, which allow the fast updating of images necessary for graphical user interfaces.

bitmap graphics or bit-map graphics A way of displaying images on a computer screen in which each picture is represented as an array of little squares called pixels. Each pixel is stored in a specific location in memory, and corresponds to one or more bits. The number of bits per pixel determines the number of colors or shades of gray that can be displayed. Bitmap graphics can be created and edited in paint programs or photo editing programs, and can be stored in a number of file formats.

Depending on file format, bitmap graphics can sometimes be imported into word processing, page layout, or spreadsheet programs, or incorporated in World Wide Web pages. Same as raster graphics; contrast vector graphics.

bitmapped font A font in which each character is formed from pixels arranged to make the shape of the character. Such an arrangement of pixels is called a bitmap.

bitmapped graphics A way of displaying images on a computer screen in which each picture is represented as an array of little squares called pixels. Each pixel is stored in a specific location in memory, and corresponds to one or more bits. The number of bits per pixel determines the number of colors or shades of gray that can be displayed. Bitmapped graphics can be created and edited in paint programs or photo editing programs, and can be stored in a number of file formats.

Depending on file format, bitmapped graphics can sometimes be imported into word processing, page layout, or spreadsheet programs, or incorporated in World Wide Web pages. Same as raster graphics; contrast vector graphics.