What is the difference between a lazy eye and strabismus?

A lot: Strabismus is the term used when the eyes do not move exactly synchronously. It is accompanied by double vision. If it is not corrected the brain ignores one of the images and in time we have a lazy eye(meaning the eye has little or no vision).

Eye function: Lazy eye is a lay term usually used to designate the vision loss that occurs when the brain turns off the eye input because it is fuzzy or misaligned (double vision). We call it amblyopia. Strabismus is a label used when the eyes don't line up and focus on the same object. Some lay people use lazy eye for both issues.