The answer is: semicolon joins two independent clauses.
The semicolon is used instead of saying the conjunction and.
Semicolons are not exchangeable with commas or periods, they are stronger than a comma but not as final as a period.
Semicolons connect two closely related independent clauses. The two sentences should share a logical and grammatical connection. The function of the semicolon is to narrow the gap between the ideas of two separate sentences or to replace a conjunction between two related ideas. They are also used to divide the items of a long list if the items are long or contain internal punctuation.
