A semicolon ';' is a punctuation mark used to connect closely linked clauses into a single sentence. It can link ideas that are related but could stand as separate sentences.
We do not use semicolons, as they can be misread. If you have a long sentence using semicolons, you should break it up into separate sentences instead.
Example
Original sentence: 'The meeting ran late; we missed the last train, the bus station was closed and we and had to find another way home'.
Rewritten sentence: 'The meeting ran late. We missed the last train and the bus station was closed. We had to find another way home'.