Creative Commons is an alternate copyright licensing practice that simplifies the restrictions put on a work in order to allow it to be shared more broadly. An item with a Creative Commons license will have a key, image or text to let you know if it can be shared for commercial and non-commercial use, if it can be shared with modification or if it only needs to be attributed to its original creator.
Fair use is protected by Section 107 of the Copyright Act that allows some use of copyrighted works in certain circumstance. More specifically, it calls for the consideration on if the use is protected by weighing these factors: Purpose and character of the use (including if it is for commercial, or nonprofit use), Nature of the copyrighted work, Amount and substantiality of the portion used in relation to the copyrighted work as a whole, Effect of the use upon the potential market for or value of the copyrighted work.
For more information on Fair Use, please see the resources below