Definition of "tramline"

tramline

/ˈtɹæmlaɪn/

noun
plural tramlines
1. (rail transport) The rails that a tram runs on.
2. (tennis, Britain) Either of the two pairs of sidelines marked on a tennis court which mark the outside of the singles and doubles playing areas.
3. (film) A scratch on a film, usually vertical, that extends through multiple frames.
  Quotations
  The tramline is therefore much less obvious on the screen. Also, if the scratch is on the base (i.e., on the back of the film), then it will not be in sharp focus.
  1984, Movie Maker, volume 18, number 2, page 47
4. (medicine) A mark or bruise having the shape of two parallel lines.
  Quotations
  The well-reported "tramlines" or parallel punctate scars on either side of the vein were seen in only four patients.
  1970 June 13, Dorothy I. Vollum, “Skin Lesions in Drug Addicts”, in British Medical Journal, volume 2, number 5710, London: British Medical Association, page 647
5. (lexicography, Oxford English Dictionary jargon) A pair of vertical bars (||) placed to the left of the headword in certain editions of the OED to indicate that the term is "alien or not fully naturalized" (such as a recent borrowing).
  Quotations
  Those words that [James] Murray classified as denizens and aliens, as well as those casuals approaching these two prior categories, were marked by two parallel lines beside the headword (||), a symbol known by the in-house term tramline. Murray himself admitted to the inherent subjectivity of his method of classification, which unsurprisingly led to a number of inconsistencies in the use of tramlines, and may even have contributed to the patchiness of the OED's regional coverage that Weiner acknowledged many years later.
  2014 May 23, Danica Salazar, “Towards improved coverage of Southeast Asian Englishes in the Oxford English Dictionary”, in Lexicography, Berlin: Springer Berlin Heidelberg