catwalk

Etymology

cat + walk

noun

1. (nautical) An elevated enclosed passage providing access fore and aft from the bridge of a merchant vessel.
2. Any similar elevated walkway.
   The lengthening [of the District Line platforms] is being done so that passengers will no longer have to use the narrow catwalks to enter and leave the front and rear portions of eight-car trains. 1963 June, “News and Comment: Victoria line engineering works”, in Modern Railways, page 370
3. A narrow elevated stage on which models parade; a runway
4. (by extension, "the catwalk") The business of making clothes for fashion shows.