The gill /ˈdʒɪl/ or teacup is a unit of measurement for volume equal to a quarter of a pint. It is no longer in common use, except in regard to the volume of alcoholic spirits measures.

In imperial units

1 imperial gill	≡ 5 imperial fluid ounces
	≡ 1⁄32 imperial gallon
	≡ 1⁄4 imperial pint
	≡ 1⁄2 Imperial cup
	≡ 10 tablespoons
	≡ 40 Imperial fluid drams
	≡ 142.0653125 mL[a]
	≈ 1.20095 US gills
	≈ 8.669357 cubic inches

In United States customary units

1 US gill	≡ 4 US fl oz
	≡ 1⁄32 US gallon
	≡ 1⁄8 US quart
	≡ 1⁄4 US pint
	≡ 1⁄2 US cup
	≡ 8 tablespoons
	≡ 24 teaspoons
	≡ 32 US fluid drams
	≡ 118.29411825 mL[b]
	≈ 0.832674 imperial gills
	≡ 7.21875 cubic inches

Prior to metrication in the United Kingdom, the standard single measure of spirits in a pub was 1⁄6 gill (23.7 mL) in England, either 1⁄5 gill (28.4 mL) or 1⁄4 gill (35.5 mL) in Scotland, and 1⁄4 gill (35.5 mL) in Northern Ireland. After metrication, this was replaced by measures of either 25 or 35 millilitres (0.176 or 0.246 gi), at the discretion of the proprietor.

Half of a gill is a jack, or one-eighth of a pint.^[1]

But in northern England, a quarter pint could also be called a jack or a noggin, rather than a gill, and in some areas a half-pint could be called a gill, particularly for beer and milk.^[2][3][4]

In Scotland, there were additional sizes:^[5]

• big gill = 1+1⁄2 gills (213.1 mL)
• wee gill = 3⁄4 gill (106.5 mL)
• wee half gill = 3⁄8 gill (53.3 mL)
• nip = 1⁄4 gill (35.5 mL)

In Ireland, the standard spirit measure was historically 1⁄4 gill in both the Republic of Ireland and Northern Ireland. It still retains this value, though it is now legally specified in metric units as 35.5 mL in the Republic of Ireland and as 35ml in Northern Ireland.

Until 2022,^[6] a spirit measure in the Isle of Man was defined as 1⁄5 gill (28.4 mL).^[7]

There are occasional references to a gill in popular culture, such as in:

• In L. Frank Baum's The Patchwork Girl of Oz, one of the ingredients required for a magic spell is a gill of water from a dark well. In chapter 19, the obscure unit is used for humor including a pun with the nursery rhyme "Jack and Jill", which also involved a well.
• In George Orwell's Animal Farm, Moses the Raven is allotted a gill of beer a day after he returns, with the implication that this is part of his payment for supporting the farm leaders, the pigs.
• Dan Simmons' novel The Terror (2007) makes frequent references to gills of grog and rum.
• In Robert Louis Stevenson's Treasure Island, there are uses of the measure gill, with Israel Hands drinking a gill of brandy in the chapter "I Strike the Jolly Roger". In Stevenson's Kidnapped the protagonist, David Balfour, is "forced" "to drink about a gill" of brandy.
• In Melvyn Bragg's memoir Back in the Day, he recalls his grandfather in the pub with "a gill of bitter" in front of him.

• The cumulative song "The Barley Mow" refers to "...the pint pot, half-a-pint, gill, half-a-gill, quarter-gill...".^[8]
• The traditional English folk song "Byker Hill" begins with the words, "If I had another penny, I would have another gill."
• The Fall's song "Edinburgh Man" contains the line "Keep me away from the Festival and just give me a warm quarter-gill."

• A gill is also referenced in Archer season 2, episode 3 ("Blood Test") when Barry explains to Archer that a liter of blood is, "about 8 gills". (Eight gills would be 32 US fl oz, or 0.95 L.) A call back reference, also discussing units of blood, is further made in season 3, episode 3 ("Heart of Archness, Part 3"). In both instances, the word is pronounced with a hard ⟨g⟩.
• In 1990's "Bart the Genius," the second episode of The Simpsons, a child tricks Bart by offering, "I'll trade you 1,000 picoliters of my milk for four gills of yours." (A picoliter is a trillionth of a liter, so Bart is losing almost a pint of milk in this exchange.)

Because of its more widely used homograph, gill has sometimes been mispronounced with a hard 'g' sound. In English, the sound of soft ⟨g⟩ is the affricate /dʒ/, as in general, giant, and gym.

• FX's animated cartoon Archer mispronounced gill in the episodes "Blood Test" (Season 2, Episode 3)^[9] and "Heart of Archness: Part Three" (Season 3, Episode 3).^[10]