In college references what is meant by "Credits" ?

In addition to the grade you earn in college classes, each class is assigned a credit value, usually between 1 and 4. Regular classes usually are 3 credits; labs like for science class are 1; advanced classes may be a 4. A normal semester class load is 12-15 credits, and usually a college has a certain number of class credits you have to earn before being awarded a degree. The credit value reflects the number of classroom hours for the class.

Typically a college course is given the description of being worth 3 credit hours or 5 credit hours. Either quarter hours or semester hours. What that describes is a course that has content that would be delivered in 3 or 5 hours of actual classroom time in a college, every week for either a quarter or a semester. Typically it is assumed that between twice and three times that will be required for studying and completing the assigned work outside of class.