The noun 'fruit' can be both countable and uncountable. The countable/plural form 'fruits' means various kinds of fruit. In fact, most nouns referring to products and substances - such as food and drink - have both a countable and uncountable form. 'Sugar', for example, is uncountable when you say 'Add some sugar', but countable when you say 'sugars' to refer to different types of sugar.

Su.Ki's answer is of great use. The countability of English nouns may be troublesome for its learners: I had thought it's only difficulty for people whose native languages have no the MUNBER category, lik Chinese, for example, but later I got to know that it may be the same for those whose languages have the category, because for a similar concept, its intention and extention may be different in different languages. Usage of FRUIT: 1. uncountable: When you are meaning 'the seed-bearing' structure of trees or other PLANTS, it indicates the part of any kind of plant, therefor it is an uncountable collective noun, which refering all kinds of things involved as a whole. ------- I like fruit and VEGETABLES. This word is often used in plual to means '(any/some) different kinds of the products by some plants. ------ Josie should eat potassium-rich foods, such as fresh fruits and vegetables, as well as drink lots of water. You cannot say (*）'a/three fruits' if you are meaning 'a/three individual pieces of fuit', because they actually mean 'a/any/three kinds of fruit'. When you need to talk about individuals, you use nouns like 'piece' to help express it. Another confusing kind of nouns are those like vegetable and plant. They are normally used as countable. In English, they respectively mean either 'the whole of things of some KIND' or 'a piece of it': the former kind of meaning can be indicated by uncountable nouns like FRUIT! Accordingly, when you say' three vegetables/plants', your may be meaning 'three types of creatures' or 'three individuals of creature'. In conclusion, the reason that English countability-variable nouns often cause trouble for learners is that a noun can mean ' the whole of all kinds of something or a specific kind' or 'a whole kind of all the individuals or an individual of the kind'. There is no evident or reasonable rules, therefor we have to learn the features of each noun specifically and this is hard work. Apart from variable nou

In British English 'fruit' is an uncountable noun but in other varieties of English it is regarded as countable. E.g. Japanese English regards fruit as countable. So, there are 5 different 'fruits' on the table is correct in Japanese English and other international Englishes but is regarded as non-standard in British and American English where such speakers would describe five different fruits on the table as simply 'fruit'.