regmacarp
A fruit which, when mature, splits open to release its seeds; a dehiscent fruit.
obsolete, rare
Dr. Master's [i.e., Maxwell T. Masters'] modification of [Alexander] Dickson's and [William Ramsay] McNab's classification of simple fruits, as to primary kinds, is into 1. Nuts, or Achænocarps, dry and indehiscent; 2. Pods, or Regmacarps, dry, dehiscent; 3. Stone-fruits, or Pyrenocarps, fleshy without, indurated within, indehiscent; 4. Berries, or Sarcocarps, fleshy throughout, indehiscent.
Where it comes from
From Ancient Greek ῥῆγμα (rhêgma, “something broken or rent asunder; a breach, cleft, fracture”) (possibly ultimately from Proto-Indo-European *bʰreg- (“to break”)) + English -carp (suffix meaning ‘part of a fruit or fruiting body’) (ultimately from Proto-Indo-European *kerp- (“to harvest; to pluck”)), modelled after schizocarp. The word was probably coined by the Scottish physician and botanist William Ramsay McNab (1844–1889): see the 1871 article from the journal Nature quoted below.
Adapted from the Wiktionary entry regmacarp (CC BY-SA 4.0).