n.
Function: noun
Etymology: Middle English, leaf, from Anglo-French fuille, foille (fr. Latin folia, plural of folium ) & fuil, from Latin folium ― more at BLADE
Date: 14th century
1 : very thin sheet metal <aluminum foil >
2 : a thin piece of material (as metal) put under an inferior or paste stone to add color or brilliance
3 : someone or something that serves as a contrast to another <acted as a foil for a comedian>
4 a : an indentation between cusps in Gothic tracery b : one of several arcs that enclose a complex figure
5 : HYDROFOIL 1