structural:expansion, structural:summarization, stylistic:tone
Etymology

According to Den Store Danske Encyklopædi and Nudansk Ordbog, the name derives from the Dutch words katte 'cat's' and gat 'gate, passage'. It derives from late medieval navigation jargon, in which captains of the Hanseatic trading fleets would compare the Danish straits to a passage so tight that even a cat would have difficulty squeezing its way through, owing to the many reefs and shoals. At one point, the passable waters were a mere 3.84 km (2.07 nmi; 4,200 yd) wide. The name of the Copenhagen street Kattesundet has a comparable etymological meaning, namely 'narrow passage', lit. ' cat's strait '.

An archaic name for both the Skagerrak and Kattegat was the Norwegian Sea or Jutland Sea (Knýtlinga saga mentions the name Jótlandshaf). Its ancient Latin name was Sinus Codanus.