1. A device that can capture an image and convert it into a unique set of electrical signals. The image scanned may be a pattern that is directly related to a code, such as bar codes on retailed products, or it may be a picture, page, or portion of text. See also drum scanner, flatbed scanner, bar code scanner, document scanner.
2. Another name for lexical analyzer.
scan·ner / ˈskanər/ • n. a device for examining, reading, or monitoring something, in particular: ∎ Med. a machine that examines the body through the use of radiation, ultrasound, or magnetic resonance imaging, as a diagnostic aid. ∎ Electr. a device that scans documents or images and converts them into digital data.