"Seed husks" refers to the protective outer covering or shell of a seed. It is like a natural armor that helps safeguard the delicate seed inside. Full definition
As well, Hairball Plus Chews for Cats contains Psyllium seed husk powder to help ease the movement of ingested fur through your cat's digestive tract. (1800petmeds.com)
It also contains Psyllium seed husk powder, a soluble fiber, which helps move hairballs through the digestive tract. (1800petmeds.com)
Quoting new roots: «Psyllium seed husks contain both soluble and insoluble fiber. (rodysheartycorner.com)