Extended Strong's Greek Lexicon (Abbott-Smith based)
under
Usage: ύπο-κάτω comp. adv. (see M, Pr., 99), [in LXX chiefly for תַּחַת ;] below, under: as prep. with genitive, Mat.22:44, Mrk.6:11 7:28 12:36 (Rec., R, txt., ὑποπόδιον, as in LXX), Luk.8:16, Jhn.1:51, Heb.2:8" (LXX), Rev.5:3, 13 6:9 12:1.† (AS)