foil

Meaning

Noun

1. A very thin sheet of metal.
2. Thin aluminium/aluminum (or, formerly, tin) used for wrapping food.
3. A thin layer of metal put between a jewel and its setting to make it seem more brilliant.
4. In literature, theatre/theater, etc., a character who helps emphasize the traits of the main character and who usually acts as an opponent or antagonist, but can also serve as the sidekick of the protagonist.
5. Anything that acts by contrast to emphasise the characteristics of something.
6. A very thin sword with a blunted (or foiled) tip
7. A thin, transparent plastic material on which marks are made and projected for the purposes of presentation. See transparency.
8. A premium trading card with a glossy finish.
9. A stylized flower or leaf.
10. Clipping of hydrofoil.
11. Clipping of aerofoil/airfoil.

Verb

1. To cover or wrap with foil.
2. Clipping of hydrofoil.

Verb

1. To prevent (something) from being accomplished.
2. To prevent (someone) from accomplishing something.
3. To blunt; to dull; to spoil.
4. (obsolete) To tread underfoot; to trample.

Verb

To expand a product of two or more algebraic expressions, typically binomials.

Verb

To defile; to soil.

Pronounced as (IPA)

/fɔɪl/

Etymology

From Middle English foyle, from Middle French fueille, from Old French fueille (“plant leaf”), from Late Latin folia, the plural of folium, mistaken as a singular feminine.
The literary sense is from the practice of backing a gem with metal foil to make it shine more brilliantly.
Doublet of folio and folium, distantly also with phyllo and phyllon.