What is the difference between a colon and a semicolon?
It’s easy to confuse these — mostly because of their similar names. In reality, they function quite differently.
Here are some quick definitions and easy ideas to keep them straight:
A colon is used to show internal information, such as equivalence, additional detail, or a list. It is helpful to think of a colon like an equal sign used in mathematics. Not only do they look kind of similar (: and =), but they function in a somewhat similar way — that is, showing that what is on one side “equals” the other side.
Example 1. Jane bought three items at the store: milk, salad, and chicken.
(In this case, three items = milk, salad, chicken.)
Example 2. I have one dream and only one dream: to become a published author.
(In this case, further detail is added — i.e., one dream = to be an author.)
A semicolon is used to show a new sentence, which is closely connected. It is replaceable with a period, so when checking your grammar, make sure that there is a full sentence before and after. Do not use these with partial sentences.*
Example 1. Basketball is fun to play; baseball is even more fun.
Example 2. Recent research has demonstrated this to be true; however, further research is needed.
* The exception is that semicolons can be used for long lists, especially when multiple commas are needed within the list. An example of this would be the following:
Careful proofreading and editing requires several steps, including checking for grammar, punctuation, spelling; reading and rereading complex sentences; and rewriting for clear, concise, and understandable communication.
As you can see, that list is complicated enough, but it would be even more complicated without semicolons. It’s often better to avoid such sentences altogether, but when they are absolutely necessary or unavoidable, semicolons can be used to save the day. Without semicolons, the sentence would be very difficult to understand. In this case, a semicolon can be a substitute for a comma.