Foil
A
foil is a type of practice weapon used in
fencing. See
foil (sword)
Foil can also refer to a
hydrofoil, a type of
boat.
A related yet different meaning of
foil is
airfoil, a type of wing or blade.
Foil can also be a short form of the longer noun
aluminium foil, a type of wrapping for food, as in "I've wrapped the sandwiches in foil".
A
foil is also a type of character in literature. See foil (literature)