foil

name

1. (mnemonic)An acronym for the algorithm for multiplying two binomials.

verb

1. (transitive)To apply the FOIL algorithm to.
2. (transitive)To cover or wrap with foil.
3. (abbreviation, alt-of, clipping)Clipping of hydrofoil.
4. To prevent (something) from being accomplished.

   “They foiled my plans.”

5. To prevent (someone) from accomplishing something.

   “I was foiled by my superior”

   “And at the field fought before Bebriacum, ere the battailes joyned, tvvo Ægles had a conflict and bickered together in all their fights: and vvhen the one of them was foyled and overcome, a third came at the very inſtant from the ſunne riſing and chaſed the Victreſſe avvay.”

   “And by mortal man at length am foil'd.”

   “her long locks that foil the painter's power”

   “Perhaps you think you love me now but it is only for an instant, and because you are foiled.”

6. To blunt; to dull; to spoil.

   “they foil the scent of one another.”

7. (obsolete)To tread underfoot; to trample.

   “King Richard […] caused the ensigns of Leopold to be pulled down and foiled underfoot.”

   “Whom he did all to pieces breake and foyle, / In filthy durt, and left so in the loathely soyle.”

8. To expand a product of two or more algebraic expressions, typically binomials.
9. (obsolete)To defile; to soil.

noun

1. (countable, uncountable)A very thin sheet of metal.
2. (countable, uncountable)A very thin sheet of plastic.
3. (uncountable)Thin aluminium/aluminum (or, formerly, tin) used for wrapping food.

   “wrap the sandwich up in foil”

4. (countable, uncountable)A thin layer of metal put between a jewel and its setting to make it seem more brilliant.
5. (countable, figuratively, uncountable)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.

   “Whereas the female invests heavily in the wake of conception, the male invests heavily prior to conception. Hitherto, the male has been regarded as the mere foil to the heavy investment in reproduction that renders the female the logjam (the limiting factor) in reproduction – reproduction overall is expandable by increasing the number of females, not by increasing the number of males.”

   “As Puss comes to realize his legendary status is not a substitute for interpersonal connection, his interactions with Kitty and the therapy dog start to take on a surprising amount of weight, while Goldilocks serves as a well-realized foil who has more in common with Puss that is at first apparent.”

6. (countable, figuratively, uncountable)Anything that acts by contrast to emphasise the characteristics of something.

   “As she a black silk cap on him begun / To set, for foil of his milk-white to serve.”

   “1725-1726, William Broome, The Odyssey Hector has also a foil to set regard”

7. (countable, uncountable)A very thin sword with a blunted (or foiled) tip.

   “Blunt as the fencer's foils, which hit, but hurt not.”

   “1784-1810, William Mitford, History of Greece Socrates contended with a foil against Demosthenes with a sword.”

   “The country’s fencing federation has officially recognised lightsaber duelling as a competitive sport, granting the weapon from George Lucas’s space saga the same status as the foil, epee and sabre, the traditional blades used at the Olympics.”

8. (countable, uncountable)A thin, transparent plastic material on which marks are made and projected for the purposes of presentation. See transparency.
9. (countable, uncountable)A premium trading card with a glossy finish.

   “I personally would collect all the foils from Base Set before this one, but the market is what the market is.”

10. (countable, uncountable)A stylized flower or leaf.
11. (abbreviation, alt-of, clipping, countable, uncountable)Clipping of hydrofoil.
12. (abbreviation, alt-of, clipping, countable, uncountable)Clipping of aerofoil/airfoil.
13. Failure when on the point of attainment; defeat; frustration; miscarriage.

    “Fame is no plant that grows on mortal foil”

    “Nor e'er was fate so near a foil.”

14. One of the incorrect answers presented in a multiple-choice test.
15. The track of an animal.

    “[…]but after giving her a dodge, here's another b— follows me upon the foil.”

16. A small arc in the tracery of a window, etc.