Rashi
a word spoken with proper basis Heb. אפניו, on its basis. An example of it is (Ps. 88:16): “I bear your terrors, it is settled (אפונה) [in my heart],” based and settled within me. This is not from the root of (Isa. 28: 27f): אפן and גלגל, wheel, for, were it so, it would be vowelized with a “pattach” under the “fe” as in (Ezek. 1:16) “האופנים the wheels.” The vowelization of the short kamatz is inappropriate for it.