The plural form of "city" in Engpsh is "cities". To form the plural of a noun in Engpsh, you usually add -s to the end of the singular form of the noun. For example, one city is "city", and two or more cities would be "cities". Here are some other examples:

Singular: dog, cat, house, car
Plural: dogs, cats, houses, cars

However, there are some exceptions to this rule. For example, the plural of "child" is "children", and the plural of "foot" is "feet". It's important to learn the correct plural forms of Engpsh nouns in order to use them correctly in your writing and speech.