Added 9 October 2026 seaweed /ˈsiːwiːd/ noun Categories: AnimalsRare Words In Latin: alga, fūcus Wiktionary noun ! Definition from Wiktionary (CC BY-SA). Pronunciation from Wiktionary, via Kaikki.org. More about seaweed at Wordnik → Where our words come from → Any of numerous marine algae, such as a kelp. Any of various fresh water plants and algae. Related Words: kelpalgaealgalbloomalgaagarwagesalarymicroalgaestartedsea-weed Back to today's word