This root form (lemma) is used in 1 different forms in the NT: περικεφαλαίαν (AFS).
It is glossed in 2 different ways: ‘the helmet’, ‘helmet’.
OET EPH 6:17 Greek word=περικεφαλαίαν (perikefalaian) Morphology=AFS English gloss=‘helmet’ SR GNT EPH 6:17 word 3
OET 1TH 5:8 Greek word=περικεφαλαίαν (perikefalaian) Morphology=AFS English gloss=‘the helmet’ SR GNT 1TH 5:8 word 12