The Hymn concertato is a genre of hymn arrangement for choir in which varied treatments of stanzas are written out, all based on the familiar tune, and almost always ending with a verse for the congregation to join on. Organ with brass instruments and/or tympani are the usual accompaniment.
The term seems to be American, although the form appears[citation needed] connected to similar works by Vaughan Williams and Holst as well as possibly to the concertato style motets of the 17th-century German composers whose descendants settled in the midwest.
A compilation of examples: https://web.archive.org/web/20070927152719/http://choralnet.org/resources/viewResource.phtml?id=2437&lang=en&category=1