A cadet branch was a familial branch from a noble family that was not directly in line for the title and corresponding estate of the family leader. Under primogeniture the firstborn child would inherit first, making his or her siblings and their heirs members of cadet branches. Morgaiah t'Thavrau was a member of a cadet branch of the Romulan House Thavrau, as her mother was niece to the house matriarch Senator Sindari t'Thavrau. (Bait and Switch: "Flaihhsam s'Spahkh")