Greek: ρομφαια [rhomphaia] (Noun Feminine). A large sword.
ρομφαια [rhomphaia] appears 7 times in the NT:
(1) Luke 2: 35
(Yea, a sword shall pierce through thy own soul also,) that the thoughts of many hearts may be revealed. - ρομφαια [rhomphaia] Nom. sing.
(2) Revelation 1: 16
And he had in his right hand seven stars: and out of his mouth went a sharp twoedged sword: and his countenance [was] as the sun shineth in his strength. - ρομφαια [rhomphaia] Nom. sing.
(3) Revelation 2: 12
And to the angel of the church in Pergamos write; These things saith he which hath the sharp sword with two edges; - την ρομφαιαν [tên rhomphaian] Accus. sing.
(4) Revelation 2: 16
Repent; or else I will come unto thee quickly, and will fight against them with the sword of my mouth. - τη ρομφαια [tê rhomphaia] Dat. sing. ("with the sword" - εν τη ρομφαια [en tê rhomphaia] Lit: "in the sword").
(5) Revelation 6: 8
And I looked, and behold a pale horse: and his name that sat on him was Death, and Hell followed with him. And power was given unto them over the fourth part of the earth, to kill with sword, and with hunger, and with death, and with the beasts of the earth. - ρομφαια [rhomphaia] Dat. sing. ("with sword" - εν ρομφαια [en rhomphaia] Lit: "in sword").
(6) Revelation 19: 15
And out of his mouth goeth a sharp sword, that with it he should smite the nations: and he shall rule them with a rod of iron: and he treadeth the winepress of the fierceness and wrath of Almighty God. - ρομφαια [rhomphaia] Nom. sing.
(7) Revelation 19: 21
And the remnant were slain with the sword of him that sat upon the horse, which [sword] proceeded out of his mouth: and all the fowls were filled with their flesh. - τη ρομφαια [tê rhomphaia] Dat. sing. ("with the sword" - εν τη ρομφαια [en tê rhomphaia] Lit: "in the sword").