Geography Coasts A-level helpWatch
A fjord is where a valley previously occupied by a glacier has been filled up by the sea, typically very long, deep and narrow (I may not be 100% accurate so check this).
(copied and pasted)
A fjard (Swedish: fjärd, IPA: [ˈfjæːɖ]) is an inlet formed by the marine submergence of formerly glaciated valleys and depressions within a rocky glaciated terrain of low relief. Fjards are characterized by a profile that is shorter, shallower, and broader than the profile of a fjord.