pen·den·tive 
(pĕn-dĕntĭv)
(pĕn-dĕntĭv)n.
Architecture
Architecture
A three-sided, curved section of vaulting between the rim of a dome and each adjacent pair of the arches that support it.
[French pendentif, from Latin pendēns, pendent-, hanging, present participle of pendēre, to hang; see (s)pen- in the Appendix of Indo-European roots.]
pendentive