A semicolon  is used to join two sentences , independent clauses  or a series of items  which are closely connected in meaning.

A semicolon separates two independent clauses that are closely related . Since both independent clauses are complete sentences, a full stop can be used in place of the semicolon.

Examples:

  • Some of them played balls and flew kites on the crowded beach; others swam in whatever space they had.
  • We sent them the packages yesterday morning; they should have received them by now.

A semicolon is used to divide a sentence into two parts, the second of which usually contains commas separating items.

Examples:

  • Some of the things we need are fresh, green salad; chunky, creamy soup; and spicy, thick sauce.
  • The cities of island countries that we have visited include St. George's, Grenada; Kingston, Jamaica; and Antananarivo, Madagascar.

A semicolon is typically placed before a conjunctive adverb  (such as however, nonetheless, therefore) that is used to connect one clause to another.

Examples:

  • He gives up smoking; obviously, he fears contracting one of the smoking-related diseases.
  • The whole article was badly written; moreover, it has some grammatical mistakes.

A semicolon cannot be used to replace a colon.

Examples:

  • No : We are looking forward to the mission; to explore the cave.
  • Yes : We are looking forward to the mission: to explore the cave.

A semicolon must not be used after a dependent clause that comes before an independent clause. The correct punctuation mark is a comma.

Examples:

  • No : Despite her parents' objections; she bought a lion cub and kept it as a pet.
  • Yes : Despite her parents' objections, she bought a lion cub and kept it as a pet.