General English

General Science

  • noun the examination of an internal part of the body using computer-interpreted X-rays to create a picture
  • noun a picture of an internal part of the body produced by computer-interpreted X-rays


  • verb to move a radar beam in a systematic pattern in search of a target


  • noun an examination of an image or object or list of items to obtain data describing it
  • verb to examine and produce data from the shape or state of an object or drawing or file or list of items


  • To move a detector or a focused beam of electromagnetic radiation, light, sound, or particles, in a fixed pattern over a surface or through a region, to sense, examine, reproduce, transmit, or the like. Seen, for example, in the tracing of the electron beam in a CRT, in the motion of a radar while searching for scanned objects, the helical path of a head in contact with a magnetic tape, or in the conversion of a scene into an electrical image.
  • A complete scan (1).
  • A scan (1) performed by an antenna, as in radars.
  • To search records, files, the Internet, or other sources of information, looking for specific data.
  • An analytical or medical diagnostic technique, such as computed tomography, in which one or more scans (1) are taken.
  • To utilize a device, such as a radar or scanner, which performs scans (1).
  • To examine while seeking something in particular. For instance, to scan communications channels looking for an available circuit.

Information & Library Science

  • verb to look at something very quickly in order to see what it is about
  • verb to examine periodicals routinely in order to keep users informed of new material
  • verb to use a machine to read coded data


  • verb to examine part of the body using computer-interpreted X-rays to create a picture of the part on a screen


  • verb to be vigilant, watch out. The standard term has been appropriated for the language of adolescent gangs. It was recorded in use among North London schoolboys in 1993 and 1994. ‘Scan out’ is a variant heard in black American speech since the 1990s.

Origin & History of “scan”

Latin scandere meant ‘climb’ (it has given English ascend and descend). In the post-classical period it was used metaphorically for ‘analyse the rising and falling rhythm of poetry’, and it was in this sense that it passed into English as scan. It was broadened out semantically to ‘examine’ in the 16th century, and to ‘look at widely’ in the 18th century. The Latin past participle scansus formed the basis of the noun scansiō, from which English gets scansion (17th c.).