This post is an attempt to keep track of the terms that differ between dialects of English or exist in some dialects but not others: British / Australian / Canadian / American / etc.
Please note that Canada may be difficult to classify, as some regions (especially near the southern border) use US terms, while others may use UK terms.
It's a community wiki, so feel free to edit and clarify or add additional items. The comments are getting long, so use answers for discussion of specific concepts if necessary, especially if you're not sure what a term means.
- Eggplant (US, AU) is an aubergine (UK).
- Zucchini (US, AU) is a courgette (UK) when harvested young or a marrow (UK) when allowed to mature further.
- Summer Squash (US) are members of the squash family with a short storage life typically harvested before full maturity; typically available starting in the spring and summer; includes zucchini, yellow and crookneck squash.
- Winter Squash (US) are members of the squash family that are allowed to reach full maturity before harvesting; typically available in the fall; includes pumpkin, acorn and butternut squash.
- Arugula (US) is rocket (UK, AU).
- Rutabaga (US) is swede (UK), but also called turnip or neep in some parts of the UK, particularly Scotland. (Wikipedia)
- Endive (US) is chicory (Belgium, perhaps others).
- Capsicum (US, AU) / bell pepper (US) is a pepper (UK).
- Seaweed (US) has many names based on type of plant, including Kombu (Japan), Nori (Japan), Laver (Wales), and many others. See (edible seaweed)
- Snow peas (US, AU) are mange tout (UK) (word borrowed from French meaning 'eat everything'). Mange tout (UK) also includes sugar snap peas (US).
- Peanuts (US) may sometimes be sold in the UK as 'monkey nuts,' especially if unshelled. And Peanut Oil may be known in the UK as groundnut oil.
- Legumes (US) are pulses (UK). 'Legume' may refer to the plant and not the seeds (lentils, beans, etc).
- Mealy potatoes (US) are floury potatoes (UK). This refers to high starch, low moisture potatoes that result in significant softening when cooked (useful for mashed potatoes or using for thickening; the opposite of waxy potatoes).
- Runner Beans (UK) are green beans or string beans (US, CA) (Farmhouse Cookery)
- Broad Beans (UK) are fava or lima beans (US, CA) (Farmhouse Cookery)
- Sultanas (UK) are seedless golden raisins (Farmhouse Cookery)
Herbs, Spices & Seasonings:
- Kosher salt (US) is flaked salt (UK). Some sea salts may be appropriate substitutes (ref).
- Cilantro (US) is known as Coriander (UK), and it tends to refer to the leaf, unless qualified as 'coriander seed'. May be qualified as 'fresh coriander' or 'green coriander'. 'Ground coriander' is always the seed.
- Coriander (US) refers to the seed.
- Celeriac (UK) is celery root (Farmhouse Cookery)
- Cookies (US, CA) are biscuits (UK, AU, NZ), while biscuits (UK, AU) refers to digestive biscuits, which are cookie shaped but more similar to a sweet cracker like the graham cracker (US, CA).
- Biscuits (US, CA) are similar to a scone (UK, AU), and usually neither sweet nor savory. Note: bisquit (Germany, no plural) is sponge cake (US).
- Muffin (US, AU) is a quick bread (typically using the 'muffin method') baked in forms used for cupcakes. It increasingly has this meaning in the UK too, with the prevalence of American-style coffee-shop chains. Muffin (UK) is english muffin (US, AU), a yeast leavened flat-ish bread, cooked on a griddle with a ring form.
- Scone (US, CA) tends to be sweeter than a scone (UK).
- Pancake (US, CA) generally refers to puffy item made from a thick leavened batter. Pancake can also be called hotcakes, griddlecakes, or flapjacks in the US. Pancake (UK) is made from a thinner unleavened batter, with a result a little thicker than a french crêpe. Drop scone (or scotch pancake) (UK) is similar to a (US, CA) pancake
- Flapjack (US) is the same thing as a pancake. But flapjack (UK) is a baked square usually consisting of sugar/honey, butter, and oats.
- Frosting (US) is icing (UK, CA, AU). In the US, frosting typically has air whipped into it, while icing (US) doesn't and dries harder.
- Turnover (US) or hand pie (US) is pasty (ˈpas-tē) (UK). (Pasties (ˈpās-tēz) in the US are coverings to comply with nudity laws in strip clubs.) 'Turnover' may be used in the UK for sweet versions (e.g. apple turnover).
- plain flour (UK) is all-purpose flour (US) (aka 'AP flour' or just 'AP' on cooking shows) unless otherwise qualified (eg, 'plain, strong flour') in which case it just means 'not self-rising'
- soft flour (UK) is lower gluten than AP flour, such as pastry flour (US) or cake flour (US)
- strong flour (UK) aka. hard flour (UK) is higher gluten flour, such as bread flour (US)
- self-rising flour (UK,US) is available in the US, but less common. Although it has baking powder in it, it does not have fat in it such as Bisquick or other 'baking mixes'.
- Ground beef (US) is minced beef (AU, UK).
- Canadian bacon (US) is also back bacon (from the loin).
- Bacon (CA, US) is streaky bacon (UK) (from the belly). In the UK, bacon is most likely back bacon.
- Green Bacon (UK) is "unsmoked bacon cured in brine" (Farmhouse Cookery)
- Gammon (UK) is "ham-like bacon from the pig's hindquarters" (Farmhouse Cookery)
- Pork rinds (US) are scratchings (UK, when dry) and crackling (AU,NZ & UK when fresh from a roast).
- Brawn (UK) is head cheese (US, CA) (Farmhouse Cookery)
- Names of cuts of meat in the US may differ from other countries. See Wikipedia for images of US and British names of regions
- Cream (US) with 5% butterfat is Single cream (UK), while cream with 48% butterfat (US) is double cream in the UK.
- Half-and-half (US) = a mix of half cream, half milk (about 12.5% butterfat)
- Light cream (US) = cream with 18 to 30% fat. But in Canada light cream = cream with 5 to 6% fat.
- Whipping cream (US) = cream with 30 to 36% fat, whereas whipping cream (CA) = cream with 35% milk fat.
- Heavy cream (US) aka heavy whipping cream (US) = cream with more than 36% fat
- Buttermilk (US, modern usage, aka 'cultured buttermilk') is a fermented product, basically a runny yogurt, while historically buttermilk is the liquid left over after churning butter, which when fresh is closer to skim milk.
- Sour cream (US) = soured cream (UK)
- powdered sugar or confectioners sugar (US) is icing sugar (UK, CA); contains cornstarch (~3%) as an anti-clumping agent.
- superfine sugar (US, CA) is caster sugar (UK, NZ, AU); may also be called berry sugar (CA), fruit sugar (CA), bar sugar, castor sugar, instant dissolving sugar, ultrafine sugar, fondant sugar, extra fine sugar.
- sanding sugar (US) is pearl sugar (CA). (size between coarse sugar & granulated sugar)
- unless otherwise qualified, sugar (US, CA) is granulated sugar
Other Food / Ingredients:
- dessert (US, AU) is pudding, sweet, dessert or afters (UK, depending on region and social class)
- pudding (US) is roughly equiv. to custard (UK)
- jello (US; brand name issues) is jelly (UK, AU)
- jelly (US) is seedless jam (UK) (see answer below for details)
- fries (US, abbr. for french fries) are chips (UK); both terms work in AU
- chips (UK) are steak fries (US)
- chips (US, AU) are crisps (UK)
- cornstarch (US) is cornflour (UK)
- corn flour (US; aka masa harina/fine corn meal) is cornflour (UK)
- cider (US) is unfiltered (cloudy) juice, commonly from apples, while cider (UK) is an alcoholic beverage made from apple juice (aka. hard cider (US) or scrumpy (UK) for stronger dry ciders)
- all-purpose flour (US) is plain flour (UK)
- liquid smoke (US) is condensed smoke, used as a flavoring.
- black beer (UK) is a malt liquor/fortified wine containing malt.
- black beer (US, Germany), also called black lager or schwarzbier is a type of lager brewed with extremely dark malt.
- tomato sauce (UK) is ketchup (US). Also catsup and other spelling variants.
- tomato sauce (US) is a tomato based sauce typically for pasta or pizza.
- marinara (US) is used synonymously with tomato sauce, and may refer to both quick or long-cooked varieties.
- tomato paste (US) is tomato purée (UK)
- tomato purée (US) is unreduced tomatoes (possibly stewed) with the skin and seeds removed. Also called crushed tomatoes.
- tomato passata (UK) (sometimes just 'passata') is strained tomato purée (US).
- golden syrup (UK) is dark cane sugar syrup (US, CA); corn syrup is an acceptable substitute (Farmhouse Cookery)
- rapeseed oil (UK) is Canola oil (US). (abbreviation for "Canada oil, low acid")
- broiling (US) is grilling (AU, UK)
- grilling (US) is barbecuing (AU)
- barbecuing (US) is slow cooking using wood or charcoal to impart smoke to the food
Tools / Equipment / Non-food items :
- parchment paper (US, CA) is greaseproof paper (Ireland/ UK, NZ)
- stove (US, CA) is also range (US, CA) and hob (UK)
- crock pot (US; brand name issues) is a slow cooker (US,UK). Also slo-cooker (UK; brand name issues)
- food processor (US, CA) is sometimes a magimix (UK; brand name issues)
- canned items (US) are tinned (UK). Items 'canned' in glass jars would be described as either 'preserved' or 'pickled' (if in vinegar) in the UK.
- recipe (US) is sometimes called a receipt in other areas and in older usage (pre-20th century).
- receipt (US, modern usage) is "a written acknowledgment of having received a specified amount of money, goods, etc."
- aluminum foil (US), aluminium foil (UK) is often referred to as tinfoil (US, UK), which had previously been in use for similar purposes.
- plastic wrap (US), cling film (UK) is often referred to as Saran™ wrap (US brand name) or Glad™ wrap (NZ, AU brand name)
- liquidiser (UK) is a blender (US, CA) (Farmhouse Cookery)
Units of measurement :
- teaspoon (US,UK, CA) is 5 mL (note: abbreviated 't' or 'tsp')
- dessert spoon (UK) is 10 mL
- tablespoon (US,UK, CA) is 15 mL (note: abbreviated 'T', 'TB', or 'tbsp') (20 mL in AU)
- A "stick" of butter (US) is 1/4 lb (113 g); the physical stick is marked into eight "tablespoon" divisions [slightly larger than an actual tablespoon]
- A "cup" (US) for cooking is a fixed measure of ~236mL (8 fluid ounces, 16 TB, 1/2 a US pint); Other countries may use a 225mL 'cup' or 250mL cup (AU, and some regions of CA?)
- A "cup" of coffee or tea (when measuring electric kettles) may be based on 5 or 6 oz 'cups'. Always look for the volume in mL or L when buying such items.
- A "gas mark" (UK) refers to the dials on some British gas ovens (Farmhouse Cookery). The marks from 1 to 9 correspond roughly to 275 - 475 °F (at 25 °F intervals) or 140 - 250 °C (at 10 °C intervals) (Conversion Chart)