ἀκρογωνιαῖος, , , a word wholly Biblical and ecclesiastical (Winer's Grammar, 99 (94); 236 (221)) (ἄκρος extreme, and γωνία corner, angle), placed at the extreme corner; λίθος cornerstone; used of Christ, 1Pe_2:6; Eph_2:20; the Sept. Isa_28:16 for τΔΜπΘΜδ ΰΖαΖο. For as the cornerstone holds together two walls, so Christ joins together as Christians, into one body dedicated to God, those who were formerly Jews and Gentiles, Eph_2:20 (yet cf. Meyer at the passage) compared with Eph_2:14; Eph_2:16-19; Eph_2:21 f And as a cornerstone contributes to sustain the edifice, but nevertheless some fall in going around the corner carelessly; so some are built up by the aid of Christ, while others stumbling at Christ perish, 1Pe_2:6-8; see γωνία, a.

ἀκρογωνιαῖος akrogōniaios 2x literally: lying at the extreme corner; with λίθος , corner or foundation stone, Eph_2:20 ; 1Pe_2:6

† ἀκρο -γωνιαῖος , -αία , -αῖον ( <ἄκροι , γωνία , an angle ), [in LXX : Isa_28:16 ( H6438 ) * ;] = Attic γωνιαῖος ( freq . in Inscr .; MM , VGT , s.v. ἀ .), at the extreme angle: ὁ ἀ ., the corner foundation stone, Eph_2:20 , 1Pe_2:6 .†

ἀκρογωνιαῖος [page 19] ἀκρογωνιαῖος may very well have been coined by the LXX ( Isa_28:16 ). The Attic word was γωνιαῖος : see inscriptional citations in J. A. Robinson Ephesians , p. 164. Crφnert (p. 233) has several other compounds of ἄκρος , some of which may be in the same category. W. W. Lloyd in CR iii. p. 419a (1889) among some architectural notes on Eph_2:20-22 , says : The acrogoniaios here is the primary foundation-stone at the angle of the structure by which the architect fixes a standard for the bearings of the walls and cross-walls throughout.

ἀκρογωνιαῖος [Etym: γωνία] "at the extreme angle", ἀκρ. λίθος "the corner foundation"-stone, NTest.

ἀκρο-γωνιαῖος, -αία, -αῖον (ἄκροι, γωνία, an angle) [in LXX: Isa.28:16 (פִּנָּה) * ;] = Attic γωνιαῖος (frequently in Inscr.; MM, VGT, see word ἀ.), at the extreme angle: ὁ ἀ., the corner foundation stone, Eph.2:20, 1Pe.2:6.† (AS)