Lexical Definition

‎θυρεός‎ thyreós (thoo-reh-os') long shield G:N-M
from ‎θύρα‎

shield.

Usage: 8 forms in 26 verses
Form Translated As     In Verse(s)
θυρεὸν shield Eph.6.16
θυρεώ shield LXX.1Chr.12.8
with a shield LXX.2Kgs.19.32
θυρεόσ shield LXX.2Sam.1.21LXX.2Sam.1.21
θυρεόν a shield LXX.Isa.37.33
an oblong shield LXX.1Chr.12.24
oblong shield LXX.1Sam.17.41LXX.1Kgs.10.17
shield LXX.2Chr.9.15LXX.2Chr.25.5
θυρεούσ oblong shields LXX.1Kgs.10.17
shields LXX.2Chr.9.15LXX.2Chr.11.12LXX.2Chr.12.9LXX.2Chr.12.10LXX.2Chr.12.11LXX.2Chr.14.8LXX.2Chr.23.9LXX.2Chr.26.14LXX.Ps.46.9LXX.Isa.21.5
θυρεού shield LXX.Ps.35.2
θυρεοίσ shields LXX.1Chr.12.34
θυρεοί shields LXX.Neh.4.16LXX.Song.4.4

Abbott-Smith

θυρεός, -οῦ, ὁ (< θύρα), [in LXX for מָגֵן, צִנָּה;]
1. in Hom., a door-stone.
2. In late Gk. (Polyb., Plut.), the scutum, a large oblong shield: θ. τ. πίστεως, Eph 6:16 (cf. Wi 5:20, where ὁσιότης is likened to the ἀσπίς, the clypeus or small round shield of the light-armed soldier).†

Abbott-Smith References

Book Refs
Ephesians 6:16

Liddell-Scott-Jones

θυρεός, ,

(θύρα) stone put against a door to keep it shut, [Refs 8th c.BC+]

__II oblong shield (shaped like a door), [Refs 3rd c.BC+], Inscription cited in [Refs 3rd c.BC+]; hence, of the Roman scutum (opposed to ἀσπίς,= clipeus), [NT+2nd c.BC+]
__III disk forming part of καθετήρ, [Refs 3rd c.BC+]
__IV in Mathematics texts, oval, [Refs 5th c.AD+]

LSJ Scripture Refs: Eph.6.16