"Subscripts" works, but they do not appear in the Scofield Reference edition, the New Oxford Annotated, or the New English Bible. For example, the site below claims that "subscripts" appear at the ends of Timothy both 1 and 2, but they are not included in the three editions I've listed above.
I wouldn't call them "glosses" at all, since they involve no scholarly commentary, Instead, they were simply additions made for putative clarification purposes but later dropped in modern editions. There is a scholarly view that they were made by Euthalius or people associated with his activities.
By the way, qp, do you actually own a copy of Strong's Concordance? I'd love to have one of my own, so tell me where you got yours!