Quick Definition
ἰσχύω v. I am strong, able
Strong's Definition
from 2479; to have (or exercise) force (literally or figuratively)
KJV Usage: be able, avail, can do(-not), could, be good, might, prevail, be of strength, be whole, + much work
UBS Dictionary of the Greek New Testament
verb | διϊσχυρίζομαι · ἐνισχύω · ἐξισχύω · ἐπισχύω · ἰσχυρός · ἰσχύς · κατισχύω
74.9 · Able, Capable
to be able to, to have the strength to, to be very capable of (derivative of ἰσχύς[a] ‘capability,’ 74.8) to have special personal ability to do or experience something
MAT 8:28 · MAT 26:40 · MRK 5:4 · MRK 9:18 · MRK 14:37 · LUK 6:48 · LUK 8:43 · LUK 13:24 · LUK 14:6 · LUK 14:29 · LUK 14:30 · LUK 20:26 · ACT 6:10 · ACT 15:10 · ACT 25:7 · ACT 27:16 · GAL 5:6 · PHP 4:13 · HEB 9:17 · JAS 5:16 · REV 12:8
79.64 · Features of Objects · Strong, Weak
to be strong enough to, to be able to, to have the strength to to be physically strong enough for some purpose
1 Note that ἰσχύω[a] may occur without a verb complement, thus making possible a translation such as to be able to do or to be able to prevail as in REV 12:8 (καὶ οὐκ ἴσχυσεν and he was not able to prevail). In some languages, however, it may be better to render this expression in REV 12:8 as he was defeated.
UBS Dictionary of the Greek New Testament © United Bible Societies, licensed CC BY-SA 4.0.
Thayer's Greek Lexicon
ἰσχύω ; impf. ἴσχυον; fut. ἰσχύσω; 1 aor. ἴσχυσα; (ἰσχύς) ; Sept. for PIT, PS, OSD, οἴο.; to be strong, i.e. 1. to be strong in body, to be robust, to be in sound health: ot ἰσχύοντες, as subst., Mt. ix. 12; Mk. ii. 17, (Soph. Tr. 234; Xen. Cyr. 6, 1, 24; joined with ὑγιαίνειν, id. mem. PB tl) 2. to have power, [fr. Aeschyl. down], i. e. a. to have a power evinced in extraordinary deeds, i. e. to exert, wield, power: so of the gospel, Acts xix. 20; Hebraistically, to have strength to overcome: οὐκ ἴσχυσαν, [A. V prevailed not i. 6.1 succumbed, were conquered, (so o> x5, Gen. xxxii. 26 (25)), Rev. xii. 8; κατά twos, against one, i.e. to use one’s strength against one, to treat him with violence, Acts xix. 16. b. i. q. to be of force, avail (Germ. gelten) : Heb. ix. 17; ri, Gal. v. 6, and Ree. in vi. 15. c. to be serviceable: εἴς τι [A. V. qood for], Mt. v.13. ἃ. foll. by inf. to be able, can: Mt. viii. 28; xxvi.40; Mk. v. 4; [ix. 18 (inf. to be supplied)]; xiv. 37; Lk. vi. 48; viii. 43; [xiii 24]; xiv. 6,29 54.; Xvi. 3; xx. 26; Jn. xxi.6; Acts vi. 10; χν. 10; xxv. 7; xxvii. 16, (Plut. Pomp.58). with ace., πάντα, Phil. iv. 13; πολύ, Jas. v.16. [Comp.: ἐν- ἐξ-, ἐπ-, κατ-ιισχύω.}
Mounce Concise Greek Dictionary
ἰσχύω ischuō 28x
to be strong, be well, be in good health, Mt. 9:12; to have power, be able, Mt. 8:28; 26:40; to have power or efficiency, avail, be valid, Gal. 5:6; Heb. 9:17; to be of service, be serviceable, Mt. 5:13; meton. to prevail, Acts 19:16; Rev. 12:8
Abbott-Smith Greek Lexicon
ἰσχύω
(< ἰσχύς), [in LXX for חזק, גִּבּוֹר, עצם, etc.;]
to be strong in body: Mt 9:12, Mk 2:17.
to be powerful, have power, prevail: Ac 19:20, Re 12:8; seq. κατά, c. gen. pers., Ac 19:16; c. inf., to be able (MM, Exp., xv): Mt 8:28 26:40, Mk 5:4 9:18 (inf. understood) 14:37, Lk 6:48 8:43 13:24 14:6, 29, 30 16:3 20:26, Jo 21:6, Ac 6:10 15:10 25:7 27:16; c. acc., Phl 4:13, Ja 5:16; of things, to avail, be serviceable (MM, Exp., xv): Mt 5:13, Ga 5:6, He 9:17 (cf. ἐν-, ἐξ-, ἐπ-, κατ-ισχύω).†
Moulton & Milligan — Vocabulary of the Greek NT
ἰσχύω. The special sense in Gal 55, Heb 91”, occurs in P Tebt II. 2867 (A.D, 121-138) νομὴ ἄδικος [οὐ]δὲν εἰσχύει, unjust possession is invalid”: cf. the use of the verb with reference to money like the Lat. va/eo, Cagnat IV. 915a'? ἡ ‘Podla δραχμὴ τούτου τοῦ δηναρίου ἰσχύει ἐν Κιβύρᾳ ἀσσάρια δέκα. For the meaning ‘‘ have power” cf. P Petr II. 18(1)} (B.C. 246) διὰ τὸ μ[ὴ]} ἰσχύειν αὐτόν pe κωλύειν, ‘ because I was not strong enough to hinder him,” and P Oxy I. 6γ}" (A.D. 338) πάντα μέν, ws ἔπος ἐστὶν εἰπεῖν, ὅσα εἰσχύειν τι δύν[α]τ[αι] παρὰ τὴν τῶν νόμων [io d]v πρὸς ὀλίγον εἰσχύει, ‘everything, it may be said, that is able to withstand the power of the law withstands but for a short time”’ (Edd.). The ordinary sense ‘‘ to be able,” without the connotation of strength, may be seen early in P Eleph 1733 (B.C. 223) διὰ τὸ μὴ εἰσχύειν αὐτοὺς καταβαλεῖν τὰς λοιπὰς avadopas, ““ because they were not able to pay the remaining imposts ” : cf. P Oxy X. 1345 (ii/iii a.p.) οὐκ ἴσχυσα ἐλθεῖν σήμερον, P Leid Wvii- *1 (ii/iii A.D.) βίβλον ἣν οὐδεὶς ἴσχυσε μεθερμηνεῦσας (1.---σαι), P Ryl II. 237° (mid. iii/a.D.) ἵνα κἀγὼ εἰς [. . - - ἐκεῖνον] εἰσχύσω συνπερινεχθῆναι (7. συμπεριενεχθῆναι) εὐχρόμως, ‘that 1 may be able to keep up appearances in my relations with him’’ (Edd.). The expressive compd. ὑπερισχύω, which is fairly frequent in the LXX, may be illustrated from P Ryl II. 119%° (a.D. 54-67) ἐν οὐδενὶ ἡγήσατο καθὸ ὑπερισχύων ἡμᾶς ἐπὶ τῶν τόπων, τ Ἢρ scorned (petitions and reports) in virtue of his superior local power” (Edd.).
Liddell-Scott-Jones — Greek-English Lexicon
ἰσχύω (ischuō) — be strong. ἰσχ-ύω (ἰσχύς), [Refs]: imperfect ἴσχυον [Refs 5th c.BC+]: future ἰσχύσω [Refs 5th c.BC+]: aorist ἴσχῡσα [Refs 5th c.BC+]: perfect ἴσχῡκα [Refs 4th c.BC+]:—passive, aorist κατ-ισχύθην [Refs 1st c.BC+]: (ἰσχύς):—to be strong in body, [Refs 5th c.BC+]; ἴσχυόν τ᾽ αὐτὸς ἐμαυτοῦ, i.e. I had all my strength, [Refs 5th c.BC+]; ἰ. ἐκ νόσου to be recovering, [Refs 5th c.BC+]
2. to be powerful, prevail, μηδὲν μεῖον ἰ. Διός [Refs 4th c.BC+]; πλέον, μεῖζον ἰ., [Refs 5th c.BC+]; later ἰ. πρός τινα prevail against, [LXX]; ἐπί τινας[LXX]; ἰ. τινί to be strong in a thing, σοφία ἀνὴρ ὑπὲρ ἀνδρὸς ἰσχύει [Refs 5th c.BC+]; ὅθεν ἰσχύομεν, ᾗπερ ἰσχύουσι, [Refs 5th c.BC+]; ἰ. παρά τινι have power or influence with one, [Refs 4th c.BC+]
2. b of things, prevail, ὅρκος οὔτι Ζηνὸς ἰ. πλέον [Refs 5th c.BC+]; τὸ δίκαιον ἐν πᾶσιν ἰ. [Refs 4th c.BC+]; have force, ἃ ὡρίσω σὺ δίκαια, ταὐτὰ.. καὶ κατὰ σοῦ προσήκει τοῖς ἄλλοις ἰσχύειν [Refs 4th c.BC+]; νομὴ ἄδικος οὐδὲν ἰ. is of no force, [Refs 2nd c.AD+]; ἰσχῦόν τι something permanent, probably in [Refs 4th c.BC+]: c.infinitive, ὁ καιρὸς ἰσχύει.. πράττειν [NT+4th c.BC+]
3. to be worth or equivalent to, ἡ μνᾶ ἰσχύει λίτρας δύο καὶ ἥμισυ [Refs 1st c.AD+]; αἱ ψῆφοι τάλαντον ἰσχύουσιν (probably to be read instead of ἴσχουσιν) [Refs 2nd c.BC+]
4. active, condense, νεφέλας [LXX]
4. b ἄρτον πᾶσαν ἡδονὴν ἰσχύοντα making strong.. ,[LXX] (in se habentem, Vulg.).
5. -ύοντες ἀστέρες those in dominating positions, Serapion in [Refs 5th c.BC+]; later, ῠ sometimes in present and imperfect, [Refs 3rd c.BC+]