What does bitmap mean?
A bitmap is a way of representing a digital image as a rectangular grid of pixels, where each pixel stores information about its color or brightness using bits — the fundamental units of computer data. Because the image is defined point by point rather than by geometric formulas, a bitmap looks natural and photographic at its native size but becomes blocky or blurry when enlarged beyond its original resolution. This distinguishes it from vector graphics, which describe shapes mathematically and can be resized indefinitely without loss of detail. Common bitmap-based file formats include BMP, JPEG, PNG, and GIF. Beyond imaging, the term also applies to data structures in which individual bits track the state of items, such as which disk sectors are free. Familiar to anyone working with photos, design software, or screen displays, 'bitmap' captures one of the core ideas of digital visual media: that a picture can be broken down into countless tiny squares of pure information.
nounA representation of a digital image as a grid of pixels, in which each pixel's color or intensity is stored as one or more bits of data. More broadly, any data structure that maps individual bits to items or positions.
- A digital image stored as a grid of pixels, each holding color or brightness values (the dominant sense in computing).
- In computing more generally, a data structure in which each bit corresponds to a flag, item, or position (as in a 'bit array' or memory bitmap).
"The designer exported the logo as a bitmap, which lost its crispness when scaled up."
"The scanner produced a high-resolution bitmap of the old photograph."
"The operating system uses a bitmap to track which blocks on the disk are free."
Standard regular plural; used when referring to multiple image files or multiple such data structures.
"The archive contained thousands of scanned bitmaps."
Every photo you've ever taken lives or dies by its bitmap — stretch it too far and those tiny squares of color betray themselves.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of bitmap
The word 'bitmap' is a modern compound formed from 'bit', short for 'binary digit', and 'map', reflecting the fact that the structure maps each position in a grid to specific bit values. It emerged in mid-20th-century computing as engineers developed ways to represent graphical displays in computer memory. Both constituent words are much older English terms — 'bit' coined by mathematician John Tukey and popularized in computing by Claude Shannon around the late 1940s, and 'map' deriving ultimately from the Latin 'mappa', meaning a cloth or chart. Related compounds include 'pixmap' (for pixel maps with color depth) and 'bit array'.
How bitmap is actually used
Primarily technical register, common in computing, graphic design, and file-format discussions. In everyday use, people often say 'image' or 'photo' instead. The .BMP file format popularized the term, though JPEG and PNG files are also bitmaps internally. Often contrasted explicitly with vector graphics.
Easily confused with bitmap
A bitmap stores images as fixed grids of pixels and degrades when enlarged, while vector graphics store shapes mathematically and scale without loss of quality.
A pixel is the single smallest picture element, whereas a bitmap is the whole data structure composed of many such pixels.