In a chapter for a course I'm taking the book discusses differentiated instruction in terms of differentiated tracking courses that took place many years ago between general education students, poor performing students, special education students, and that often related to different races and cultures.
Nowadays this word is all about how we cater lessons to suit different students in our class. Always remember, differentiation means holding all of our students to the same standards and making sure all of them can reach, grab, and learn