Abbott-Smith Manual Greek Lexicon
ὑπό-στασις (G5287)
5 (KJV) ὑπό-στασις , -εως, ἡ ( ὑφίστημι , to set under, stand under, support ) [in LXX for מַצָּב ( I Ki 13:23 14:4 B), תִּקְוָה ( Ru 1:12 , Ez 19:5 ), etc., also in Wi 16:21 ;] a support, base or foundation (in various senses). substance (Arist., al.; opp. to φαντασία, ἔμφασις ): He 1:3 steadiness, firmness (Polyb., al.), hence, assurance, confidence : II Co 9:4 11:17 , He 3:14 11:1 (here perhaps title-deed, as that which gives reality or guarantee; v. MM, xxv).†
G. Abbott-Smith, A Manual Greek Lexicon of the New Testament (1922) — public domain