extramural (adj.)

word-forming element meaning "outside; beyond the scope of; in addition to what is usual or expected," in classical Latin recorded only in extraordinarius, but more used in Medieval Latin and modern formations; it represents Latin extra (adv.) "on the outside, without, except," the old fem. ablative singular of exterus "outward, outside," comparative of ex "out of" (see ex-).

1650s, from Latin intermuralis "situated between walls," from inter "between" (see inter-) + murus (genitive muralis) "wall" (see mural).