UK English is a type of English used in the United Kingdom, while US English is a type used in the United States. One of the major differences between the two can be noticed in terms of vocabulary. There are certain words in UK English that do not have the same meaning as the one used in the United States.
For instance, the word biscuit in UK English is chiefly used for a small, flat, baked savory cake, which is hard and crisp. In contrast, the word is used to describe a small quick bread that is made from dough. In terms of pronunciation, you might also notice some little differences between the two types of English.
Certain words in UK English and US English are stressed differently. For instance, some words in UK English are pronounced by stressing the second syllable, whereas you will be stressing the first syllable if you are using those words in US English.