sort of like asking about the St Vincent part of Enda St Vincent Millay's name.

She was named Edna St. Vincent Millay because her uncle, was accidently injured, and was left unconscious in a ship's hold(he was checking goods he was having shipped, and was planning to leave on the same ship, leaving england) He was there 10 days, with no food or water, and very near death when found in NY.
he was rushed to St Vincents Hosp., and survived. His sister, close to term at the time, promised to name her child for the hospital, to thank them..

So Edna St Vincent Millay was named for a hospital.

what is the term used to descibe that?