Misinformation is false information that is spread by people who mistakenly believe it to be true, while disinformation is false information that is spread with the intent to deceive or mislead others (Encyclopedia Britannica).
You might also hear the term "fake news," which is a type of disinformation created and shared for commercial or political reasons. Often you'll see provocative headlines or titles for the purpose of getting you to click through to advertising. Some politicians or media personalities use the term to describe sources that oppose their views, or to discredit a legitimate source.
Regardless of intent or motivation, spreading inaccurate information can cause significant harm. We all share the responsibility of stopping its spread by being critical consumers of information and checking our sources before we share something online. The SIFT method provides great strategies for this.
The International Federation of Library Associations created an infographic with additional tips:
There are multiple tools available to help you check online sources. The VSCS Libraries has a list of fact checking tools on the Misinformation and Fact Checking page in the How to Do Research section of the library website.