I'm afraid it rarely helps to ask "why" questions. I think your question is legitimate, because "vegetables" is different from other logically similar words. I'm not sure there's any definitive answer, and I can't think of any memory trick to remember which is which. I can imagine my wife sending me to the grocery store and saying any of these things, and I can't point to any obvious logical differences: "We need to get some groceries." "We need to get some fruit." "We need to get some vegetables." "We need to get some meat." "We need to get some apples." "We need to get some chicken." "We need to get hamburger, so that I can make hamburgers." It is possible for the same word to exist both as an uncountable and as a countable noun. The countable form refers to kinds or types or categories. For example, "meat" is usually an uncountable noun. "My friend won't each meat, she only eats vegetables." But you could say "the supermarket has a good selection of meats, including beef, pork, lamb, chicken, and turkey." Similarly: "We don't have any cereal in the house. Get some cereal. "What kind?" "My favorite cereals are cornflakes and granola." I'm going to try for a logical answer, but I'm just making this up and I can't be sure it's true. I think "vegetables" is almost always countable because we almost always use the word to mean a category or kind of food. If my plate has fifty peas and two potatoes on it, I say "I have two vegetables," not "I have fifty-two vegetables." "Vegetable" can be used without an "s" as an adjective. In that use, it doesn't mean "one," it almost feels uncountable to me: "They have carrots and celery in the vegetable section." "Some parts of the world subsist mainly on a vegetable diet."

Hi Fiona Let us first understand the following terms - Countable nouns – The nouns which can be counted are known as countable nouns. We can count these nouns using numbers and they can have both singulars as well as plural forms. The singular form will use a/an in the sentences while the plural form will have a count(number) of the noun. For e.g. a puppy (singular form), 5 puppies(plural form). These words are accompanied by articles and quantifiers. Uncountable nouns- As the name suggests, these are the nouns that cannot be counted. These nouns are usually given in singular forms as they do not have any plural forms. These nouns can be found in the form of an abstract idea, a feeling or they may have such little quantity which cannot be counted. For e.g. rice, rain etc. These words are accompanied by some, any, a little, and much. vegetables is a countable noun. it has both a singular and a plural form. for example: They grew their own vegetables (NOT their own vegetable). Using the word in plural form basically refers to all the various types of vegetables; i.e. carrots, tomatoes, parsley, etc.

I find the concept of "countable" to be a not very useful. I can make a plural out of just about any noun. For instance, Reza mentioned "rice" and "rain" as examples. Her point is well taken that we commonly accompany these nouns by "some, any, or much". However, I can easily make up a sentence mentioning 5 rices or 5 rains that makes perfect sense. For instance I have 3 rices in my cabinet: short grain brown rice, white rice, and suchi rice. So, "countable" and "not countable" are vague, poorly defined concepts. Even "money" has a plural "monies" (which you shouldn't use unless you understand what it means). So, countable vs not countable is a misleading distraction. It is better to concentrate on "collective nouns" and customary usage.

Hi Fiona, it really depends on the situation. Others have given good ways to look at this whole countable vs uncountable issue. I recommend doing exercises on this or reading more. The more exposure you have, the better you can distinguish between which to use: vegetable/vegetables. Hope this helps! :)

Why is this word countable but money is uncountable?