The story
From the ocularium (vision slit) looking like a frog's mouth.
Etymology from Wiktionary, CC BY-SA 4.0.
frog-mouth helm
Today it means: great helm (close helmet) derivative specifically for tournament jousting Full definition →
Today it means: great helm (close helmet) derivative specifically for tournament jousting Full definition →
From the ocularium (vision slit) looking like a frog's mouth.
Etymology from Wiktionary, CC BY-SA 4.0.