I entirely agree. Inviting people round to dinner is one of life’s pleasures. I do the cooking and Mrs Bob does the table etc. Food (hopefully good, though I have been known to fail), good wine, and above all good company.
How to Boil Water <excellent book for the truly beginner cook. I like it because it doesn’t stop with grilled cheese and salad (although those are in there) but also includes recipes with slightly more exotic ingredients, like fresh herbs and fresh mozzarella - nothing you can’t find at a decent supermarket, but real grown up food.
Because (as you indicate) arbitrary measurements make little sense in a recipe, it might have been wise to infer the possibility of this being a standard unit of measure. A search on “cup unit” readily confirms this.
Actually, 236.588.
No, 238 ml is indeed more accurate than 250 ml, as stated.
As you have seen here, a “cup” in a cooking recipe is not random, generic, nor arbitrary. I’m quite curious, however, how you came to have a cookbook that uses this term whereas you were not familiar with it. A gift from overseas, perhaps?
Ha! Here’s what Cooking for Engineers has to say about Nestlé Toll House Cookies:
The author conducted several tests, resulting in a ‘trashcan full of excess cookies, empty Costco bags of Toll House morsels, and a colleague… who ate over 2000 calories of soft, gooey cookies during two or three hours…’, and concluded that the intended amount of flour in the recipe was 160 g per cup, or 360 g total for the recipe. So in this case, the flour is to be scooped out of the bin as-is. The author says that the best way to achieve repeatable results is to sift the flour and measure by weight. For the cookies, that would be 2.75 cups of sifted flour.
Speaking of ‘cups’, my coffee maker says it makes 12 cups. It doesn’t. It fills my coffee cup four or five times. It seems a ‘cup’ of coffee is six fluid ounces.
Cooking needn’t be precise. I like to follow the recipe the first time I make something so that I can expect the result to be as the recipe-writer intended. Following a recipe is handy when I’m making something I don’t make often, as well. But once I’m comfortable with a dish, or if I’m improvising, I use the TLAR method.
I do have the nested measuring cups, but I find them useful for approximations. If I want to be more precise, I use a one-cup or two-cup glass measuring cup. These are graduated in fractions of cups, ounces, and millilitres, and you can see the meniscus for liquid measurements. But as I said, cooking isn’t that precise. Just get the ratios approximately right, and you’ll be fine. But the glass measuring cups are handier (for me) than the nested metal or plastic ones.
There is, however, the infuriating (to a new cook) “to taste” measurement! As in, “salt and pepper to taste” or even worse, “oregano, to taste.”
“To taste” means - as much or as little as you need to get it to taste how you like it. This isn’t so annoying for salt and pepper, as you can add a little, taste it, and add more and see how it changes. As long as you go slowly, you can generally find the point where it’s perfect for you.
But there are some things, like oregano and garlic, which change dramatically in flavor as you cook them! So putting “to taste” for those kinds of ingredients is killer on a new cook. An experienced cook will know about how much oregano a dish needs even if it’s a new recipe. A beginner has no idea! They’ve got to guess, and then taste the finished dish and if it tastes awful, they’ve got to try to guess which ingredient did it and if it was too little or too much. :smack:
My family is notorious for the measurement, “enough”. As in, “how much vinegar do I add?” “Enough.” Related measurements are “so much,” “a skosh,” “a bit,” “a dollop” and “some.” Luckily for the world, we only inflict such “recipes” on each other, and not for publication! 
There are some things that it just makes no sense to specify by volume. “Add 1/2 cup of mushrooms/tomatoes” is meaningless. Chopped? Whole? Diced?
[QUOTE=Johnny L.A.]
It seems a ‘cup’ of coffee is six fluid ounces.
[/QUOTE]
Yes it is. I’m not sure why the coffee people chose to be ornery and concoct their own definition for a “cup” but there it is - six fluid ounces of coffee per cup.
Unless people are into demitasse servings, nobody drinks a “cup” of coffee - my coffee “cup” at work measures out to a comfortable 20 ounces.
Almost always, the stated amount for that type of thing is meaningless. Chopped, whole, minced, or diced should be obvious based on what you’re making; but I find the amount is usually too little. Too much salt or a particular spice is one thing. But bulky things like vegetables or shredded cheese or meat is another.
Moderator Action
Since this thread has progressed beyond the factual question asked in the OP and has moved on to include general cooking advice (and it has made me develop a sudden craving for cookies), let’s move it over to Cafe Society.
Moving thread from General Questions to Cafe Society.
IF the OP is from an English-speaking country other than the USA, why is he (or she) encountering cookbooks with recipes that call for CUPS (as opposed to metric weights [or more pedantically, masses])?
Rice cookers ask for a ‘cup’ of rice or water, but they invariably mean that little plastic cup that comes with it, which is only 180 ml.
Edit: kaylasdad99, my guesses were second-hand cookbooks, or perhaps cookbooks bought from overseas (even via Kindle etc.) by various ‘celebrity’ chefs or that are supposed to be ‘standard’ cookbooks but weren’t converted for the local market. As an American, I’ve bought cookbooks from the UK or Australia that obviously were written with their home audience in mind. Some US cookbook writers try to take metric measurements into consideration as a secondarily-noted measurement, but with varying levels of success.
You can certainly buy US measuring cups in Canada and most of our recipes use them. I find cups quite convenient. In most cases, the measurements are not crucial. I mean if a recipe calls for 2 cloves of garlic, you can see that that is horribly imprecise. In the end you have to use your judgment. I find it quite easy to cook using volumetric measurements. I do own a scale but rarely use it.
BTW, the US and Imperial ounce are also not the same. So that a US pint is about 5/6 (not 4/5) of an Imperial pint. Does that matter in cooking? Short answer: no.
Cups are easy to use. You never pack flour into a measure cup. Scoop it full and gently level off the top with a knife. Simple.
Sometimes a recipe will tell you to pack the cup. Thats usually brown sugar. I can’t think of anything else.
liquid measures are based on factors of 8
8 oz to a cup
16 oz to a pint
32 oz to a quart
64 oz half gallon
128 oz in a gallon
2 tablespoons equals 1 oz
You need to retain space for the head or the beer goes all over the bar.
And as an ingredient list really only shows the proportions of each ingredient, if you consistently use the same measuring tools you will end up with a fair approximation of what the writer intended. The art comes from knowing the adjustments to make so it tastes the best to you. To wit:
I use “about yea” a lot, but I am giving visual demonstration at the time. Cooking is a skill learned by doing it, and recipes are just rough guidelines. America’s Test Kitchen, though, claims its recipes are the results of many experiments, and even the failure were probably pretty darn good. I’d be morbidly obese if I worked there. Oh, wait… 
This. For a lot of things, a wide range is close enough. So a “cup” is about a quarter liter, and you can use a little more or less to suit your taste.
Asking my wife, the only exception would be making cake from scratch, where the ingredients need to be in the right proportion. It’s important for bread, but you need to do that by feel (she says). You can add a little water or a little flour to get the right consistency.
Please allow me to fill in some blank spots.
When measuring liquids, surface tension pulls the liquid a little higher than the actual surface (that’s called the meniscus.) To get a standard cup, the top of the meniscus comes to the line.
For dry measures, fill a little above the measuring cup, and level it off by dragging a straight edge across the top.
In the coffee making world, for some reason, a cup is 5 ounces.
Flour is tricky stuff. Scooping it up can compress it, and sifting can inflate it unreliably. It’s better to weigh it. The chart I use says a cup of flour is 140g. If you’re paying attention, you noticed that differs from the chart in Bozuit’s link. In my bread making, 140 works very well.
You left out “until it smells right”, which is a point of minor contention in my family.