Lexical Definition

‎τηρέω‎ tēréō (tay-reh'-o) to keep: observe ^G:V
from (a watch

hold fast, keep(- er), (pre-, re-)serve, watch.

• perhaps akin to ‎θεωρέω‎)
• to guard (from loss or injury, properly, by keeping the eye upon
• and thus differing from ‎φυλάσσω‎, which is properly to prevent escaping
• and from ‎κουστωδία‎, which implies a fortress or full military lines of apparatus), i.e. to note (a prophecy
• figuratively, to fulfil a command)
• by implication, to detain (in custody
• figuratively, to maintain)
• by extension, to withhold (for personal ends
• figuratively, to keep unmarried)
• by extension, to withhold (for personal ends
• figuratively, to keep unmarried)

Abbott-Smith

τηρέω, -ῶ [in LXX for שָׁמַר, נָצַר, etc. ;]
1. to watch over, guard, keep, preserve: Mt 27:36, Ac 16:23, al.; ἑαυτόν, II Co 11:9, I Ti 5:22, Ja 1:27, Ju 21; seq. εἰς, Jo 12:7, Ac 25:21, I Pe 1:4, II Pe 2:4, 9 3:7, Ju 6; ἐν, Jo 17:11, 12, Ju 21; ἐκ, Jo 17:15, Re 3:10; τ. πίστιν, II Ti 4:7, Re 14:12; τ. ἑνότητα τ. πνεύματος, Eph 4:3.
2. to watch, give heed to, observe: τ. σάββατον, Jo 9:16; τ. ἐντολήν (-άς), Mt 19:17, Jo 14:15 15:10, I Ti 6:14, I Jo 2:3, 4 3:22, 24 5:3, Re 12:17 14:12; τ. λόγον (-ους), Jo 8:51, 52, 55 14:23, 24 15:20 17:6, I Jo 2:5, Re 3:8, 10 22:7, 9; τ. νόμον, Ac 15:5, Ja 2:10; τ. παράδοσιν, Mk 7:9; τ. ἔργα, Re 2:26; τ. γεγραμμένα, Re 1:3 (cf. δια-, παρα-, συν-τηρέω)
SYN.: φυλάσσω, implying custody and protection: τ. expresses the idea of watchful care and "may mark the result of which φ. is the means" (Thayer s.v.).

Abbott-Smith References

Liddell-Scott-Jones

τηρέω-έω

(τη- also in Doric dialect, [τηρέωέω)">Refs 7th c.BC+], perfect τετήρηκα [Refs 4th c.BC+]:—watch over, take care of, guard, δώματα [Refs 5th c.BC+]; rarely of persons, δαιμόνων.., αἵτινες τηρέωοῦμεν ὑμᾶς [Refs 5th c.BC+]; τ. τὴν ἀρχήν maintain it, [Refs 2nd c.BC+] —passive, τὸ ἔξωθεν [τεῖχος] ἐτηρέωεῖτο was constantly guarded, [Refs 5th c.BC+]future middle τηρέωήσομαι in passive sense, [Refs]

__2 τ. ὅπως.. ἔσται take care that.. , [Refs 4th c.BC+]; τ. μὴ.. cavere ne.. , [Refs 5th c.BC+]: also in middle, τηρέωώμεσθ᾽, ὅπως μὴ.. αἰσθήσεται [τηρέωοῦ μὴ λάβῃς ὑπώπια [prev. work] 1386. ">Refs 5th c.BC+]
__3 τηρέωεῖν ἀπὸ τοῦ πυρός protect them from the fire, i.e. cook them slowly, Bilabel Ὀψαρτ.[Refs]
__II give heed to, watch narrowly, observe, τηρέωῶ αὐτοὺς οὐδὲ δοκῶν ὁρᾶν κλέπτοντας [Refs 5th c.BC+]
__II.2 watch for a person or thing, with a participle, παραστείχοντα τηρέωήσας [Refs 5th c.BC+]; ἔνδον ὄντα τηρέωήσαντες αὐτόν having watched for his being within, [Refs 5th c.BC+]; τ. τὸν πορθμὸν κατιόντος τοῦ ἀνέμου watching for a crossing with the wind blowing down, [Refs]; τ. τινὰ ἀνιόντα watch for one's coming up, [τηρέωῆσαι 5th c.BC: Thucydides Historicus 1.65; τ. νύκτα χειμέριον [prev. author] 3.22, compare 4.27 ">Refs 5th c.BC+]; νύκτα καὶ ὕδωρ, [Refs 4th c.BC+]; τὴν θήραν τ. [Refs] —passive, ὁ καιρὸς ἐτηρέωήθη was watched for, [Refs 5th c.BC+]
__II.3 absolutely, watch, keep watch, [Refs 5th c.BC+]: with infinitive, watch or look out, so as to.., ἐτήρουν ἀνέμῳ καταφέρεσθαι [Refs 5th c.BC+]
__II.4 observe, notice, [μετακόσμησιν σωμάτων] [Refs 2nd c.AD+]
__II.5 test by observation or trial, τετηρέωημένον βοήθημα an approved method of treatment, [Refs 2nd c.AD+]; as Empiric term, τετηρέωημένης ἐπ᾽ αὐτοῖς τῆς θεραπείας, οὐκ ἐνδεικτικῶς εὑρισκομένης [τηρέωῆσθαι φλεβοτομίαν [prev. author] 15.766. ">Refs 2nd c.AD+]
__III observe or keep an engagement, ὅρκους [NT+5th c.BC+]
__III.2 preserve, retain, τὰς αἰσθήσεις uncertain in [Refs 5th c.BC+]

_{LSJ Scripture Refs: 2Tim.4.7}