Quick Definition
θεμέλιος, ον n.m. & n.n. belonging to the foundation
Strong's Definition
from a derivative of 5087; something put down, i.e. a substruction (of a building, etc.), (literally or figuratively)
KJV Usage: foundation
UBS Dictionary of the Greek New Testament
noun, m. | -ου | τίθημι
7.41 · Constructions · Parts and Areas of Buildings
foundation that on which a structure is built In some languages it is possible to describe a typical foundation in ancient times as ‘large stones underneath the walls.’ In other languages, however, this may seem to be quite a meaningless type of expression, since foundations are only made secure by driving stakes deep into the ground. Therefore, it may be best to describe the function of a foundation by ‘what keeps the walls firm’ or ‘how the walls are made not to move’ or ‘what goes beneath the walls.’
LUK 6:48 · LUK 6:49 · LUK 14:29 · ACT 16:26 · ROM 15:20 · 1CO 3:10 · 1CO 3:12 · EPH 2:20 · HEB 11:10
7.43 · Constructions · Parts and Areas of Buildings
foundation stone a stone used in the construction of a foundation Such foundation stones may be described as ‘stones beneath the walls’ or ‘stones beneath the walls to make the walls strong.’
1 In Greek literature θεμέλιος (masc.) and θεμέλιον (neuter) occur in the meaning of ‘foundation,’ but in the NT θεμέλιον in the sense of ‘foundation’ happens to occur only in the plural form (ACT 16:26). 2 λίθος in the sense of ‘building stone’ (that is, a shaped stone in contrast with a field stone) is treated in Domain 2 Natural Substances (2.24).
UBS Dictionary of the Greek New Testament © United Bible Societies, licensed CC BY-SA 4.0.
Thayer's Greek Lexicon
θεμέλιος, -ον, (θέμα [i. 6. thing laid down]), laid down as a foundation, belonging to a foundation, (Diod. 5, 66; θεμέλιοι λίθοι, Arstph. av. 1137); generally as a subst., ὁ θεμέλιος [se. λίθος] (1 Co. iii. 11 sq.; 2 Tim. ii. 19; Rev. xxi. 19), and τὸ θεμέλιον (rarely so in Grk. writ., as [Ar istot. phys. auscult. 2,9 p. 200", 41: Paus. 8, 32,1; [al.]), the foundation (of a building, wall, city): prop., Lk. vi. 49; τιθέναι θεμέλιον, Lk. vi. 48; xiv. 29; plur. οἱ θεμέλιοι (chiefly so in Grk. writ.), Heb. xi. 10; Rey. xxi. 14, 19; neut. ro Oey. Acts xvi. 26 (and often in the Sept.) ; metaph. the foundations, beginnings, first principles, of an institution or system of truth: 1 Co. iii. 10, 12; the rudiments, first principles, of Christian life and knowledge, Heb. vi. 1 (μετανοίας gen. of apposition [W. 531 (494)]); a course of instruction begun by a teacher, Ro. xv. 20; Christ is called θεμέλ. i. 6. faith in him, which is like a foundation laid in the soul on which is built up the fuller and richer knowledge of saving truth, 1 Co. iii. 11; τῶν ἀποστόλων (gen. of appos., on account of what follows: ὄντος . . . Χριστοῦ, [al. say gen. of origin, see ἐποικοδομέω; cf. W. § 30,1; Meyer or Ellicott ad loc.]), of the apostles as preachers of salvation, upon which foundation the Christian church has been built, Fph. ii. 20; a solid and stable spiritual possession, on which resting as on a foundation they may strive to lay hold on eternal life, 1 Tim. vi. 19; the church is apparently called θεμ. as the foundation of the ‘city of God,’ 2 Tim. ii. 19, cf. 20 and 1 Tim. iii. 15. (Sept. several times also for })278, a palace, Is. xxv. 2; Jer. vi. 5; Amos i. 4, ete.)
Mounce Concise Greek Dictionary
θεμέλιον themelion 1x
in Acts 16:26 themelion is used as a neuter noun from themelios (G2529), foundation such as the foundation of a prison*
Abbott-Smith Greek Lexicon
θεμέλιος, -ον
(< τίθημι), [in LXX for אַרְמוֹן, מוֹסָד, etc.;]
of or for a foundation; as subst., ὁ θ. (sc. λίθος), a foundation stone, foundation: Lk 6:48, 49 14:29 (but v. Deiss., BS, 123); pl., οἰ θ. (cl.), He 11:10, Re 21:14, 19; neut., τὸ θ. (Arist., Phys., vi, 6, 10, LXX and later writers), Ac 16:26; metaph., Ro 15:20, I Co 3:10-12, Eph 2:20, I Ti 6:19, II Ti 2:19, He 6:1.†
Moulton & Milligan — Vocabulary of the Greek NT
θεμέλιος. The neut. τὸ θεμέλιον can be seen in P Petr II. 14(3)? (as completed Introd. p. 30—iii/B.C.) εἰς ? τὸ θεμέλιον ψύξαι, **for drying the foundation,” 26. III. 46(4)4 τοῖς τὸ θεμέλιον ὀρύξασι € ““ἴο those who dug the foundation, 5 (drachmae),’’ and the plur., as in Ac 1678 (cf. Prov 839), in P Strass I. 98 (¢. A.D. 307 or 352) πηχισμοῖς kal θεμελίοις kal τίχεσιν, and P Lond 1215!® (iii/a.p.) (=I. p. 101) καὶ ἐκεινήθη τῆς γῆς τὰ 5 θεμείλια. In P Magd 274 (B.C, 218) βιάζεταί με πλίνθον προσάγων καὶ θεμέλιον σκάπτων ὥστε οἰκοδομεῖν, the gender is indeterminable, as in a number of the NT passages. So Chrest. 11. 68% (A.D. 14) ods Kal ἀνοικοδόμησα ἐπὶ τῶι [ἀρχ]α[(]ωι θεμελίωι, P Lond 9911 (vi/A.D.) (ΞΞ- ΠΙ. p. 258) ἀπὸ θεμελίου ἕως ἀέρως, Mechel 11855 (ii/B.c.) ἐκ θεμελίω. For the LXX usage, see Thackeray Gr. i. p. 154f., and cf. Moeris p. 185; θεμέλιον Kal θεμέλια, οὐδετέρως, ᾿Αττικῶς.
Liddell-Scott-Jones — Greek-English Lexicon
θεμέλιος (themelios) — foundation. θεμέλῐ-ος, ον, of or for the foundation, λίθοι [Refs 5th c.BC+], ὁ, foundation-stone, [Refs 4th c.BC+]; οἱ θ. ἐκ παντοίων λίθων ὑπόκεινται the foundations, [Refs 5th c.BC+]: also neuter θεμέλιον [Refs 4th c.BC+], of the foundations of the world, [Refs 5th c.BC+]; ἐκ τῶν θ. from the foundations, [Refs 5th c.BC+]: metaphorically, ἐκθ. ἐσφαλμένοι [Refs 2nd c.BC+]; also ἀνεκτίσθη τὸ τεῖχος ἐκ θεμελείων (sic) [Refs 4th c.AD+]
II. θεμέλια, τά, buildingsites, [Refs 2nd c.AD+]
III. substantive, the fourth τόπος,= ἀντιμεσουράνημα, Herm.Trism. in [Refs]