IPA: //ˈsiːkræft//
KK: /ˈsiːkræft/
A type of vehicle designed to travel on water, especially in the ocean.
The seacraft sailed smoothly across the waves.
Seacraft is formed from "sea" (from Old English "sǣ", meaning the large body of saltwater) and "craft" (from Old English "cræft", meaning skill or strength). The word "seacraft" refers to the skill or craft related to navigating or operating on the sea.
Think of the 'sea' as the large body of water and 'craft' as the skill involved in navigating it — that's why seacraft means the skill of operating on the sea.