The Semicolon ( ; semi-colon )

The semicolon is used to separate independent clauses See the glossary definition, and to separate items in a list. Whereas the colon moves the reader forward providing an elaboration of what went before (in the form of an example or definition), the semicolon only acts as a separator.

1. Semicolon separating independent clauses

   • Most foods contain at least some sugarindependent clause; semicolon introducing independent clause once foods are between 230 and 320 degrees, their sugars begin to turn brownsecond independent clause.
   • For instance, our Milky Way galaxy has at least 100 billion starsindependent clause; semicolon introducing independent clause that means it has at least 100 billion planets toosecond independent clause.
   • The best-performing chimpanzees remembered at least four itemsindependent clause; semicolon introducing independent clause one young chimpanzee remembered more than sevensecond independent clause.

   A sentence containing independent clauses not separated by a semicolon is known as a run-on See the glossary definition sentence.

   
   

2. Semicolon for separating items in a list

   We already have commas for separating items in a list, so why do we need to use the semicolon? The reason is that sometimes the items in the list are long and may themselves contain commas. It this case we need another separator to avoid confusion.

   • Our Earth is structured sort of like an onion – it’s one layer after another. Starting from the top down, there’s the crust, which includes the surface you walk onfirst item in the list (of layers) - we have two commas in this item so using another to separate it from the next item would be confusing; semicolon separating list items then farther down, the mantle, mostly solid rocksecond list item, also containing commas; semicolon separating list items then even deeper, the outer core, made of liquid ironthird list item, also containing commas; semicolon separating list items and finally, the inner core, made of solid iron, and with a radius that’s 70% the size of the Moon’sfourth list item, also containing commas.
   • The evaluation process for a classification includes: colon introducing a list medical, visual or cognitive testingfirst list item, containing a comma (this phrase is itself a list); semicolon separating list items demonstration of sport skillssecond list item; semicolon separating list items and observation during competitionthird list item.

Test your understanding of semicolon punctuation with the Colon/Semicolon Punctuation Quiz.