BT BB 63b(11) :אהני עומקא ורומא למקני עומקא ורומא‏ : (the phrase) 'depth and height' (in a contract) is effective to acquire possession concerning 'depth and height' [i.e. the space below and above]
See the entire entry for ˁŭmoq, ˁumqā n.m. depth; valley