A seed was a biological component of a plant from which new plants of the same species could grow. The Amarylls also used their seeds for self-defence, as they could be launched at enemies and grow immediately, choking them. (COMIC: The Amaryll Challenge)
The star seed was a highly unusual type of seed manufactured by Villengard which became a star upon blooming. (TV: Joy to the World [+]Steven Moffat, Doctor Who series 15 (BBC One and Disney+, 2024).)
Other references
Maple Seed was a business active in London at the time of the March of the Adipose. (TV: Partners in Crime)
Veklin compared Falkus to Dalek seed vault. (AUDIO: A Genius for War)