From hept- + angular. <span class="searchmatch">heptangular</span> (not comparable) heptagonal...
六(ろっ)角(かく)錐(すい) (rokkakusui, “hexangular pyramid”) 七(なな)角(かく)錐(すい) (nanakakusui, “<span class="searchmatch">heptangular</span> pyramid”) 八(はっ)角(かく)錐(すい) (hakkakusui, “octangular pyramid”) 円(えん)錐(すい)...
angular-winged katydid biangular decangular distoangular equangular equiangular <span class="searchmatch">heptangular</span> hexangular inangular interangular mesioangular multiangular nonangular...