Counter-arch
Historically, the term counter-arch was used in architecture to describe multiple types of arches that provide opposing action: an inverted arch used opposite of a regular one. For example, an inverted arch in an open spandrel or in "Moseley bridges", a popular American Civil War-era design by Thomas William Moseley, where the counter-arches were intended as a low-cost alternative to diagonal bracing; any relieving arch; outer "rings" of compound arches overlaying the one forming the intrados, used in old English bridges since medieval times, are called "counter-arches" following the works of John Smeaton; an arch that is built adjacent to another arch to oppose its forces or help stabilize it.