Based on your question, I would recommend posting some of the example sentences where you have seen this word. the below is a copy paste (credit Dictionary.com) of the variety of uses. I also see it now has a use in "urban slang" - see point 5. 1 - having a specified object or material as its base or foundation or as its primary constituent (often used in combination): Our house was one of the three stone-based houses of that era, built by my maternal grandfather. 2 - established, grounded, or focused on a specified principle or belief, fact, method, etc. (often used in combination): It’s a culturally based phys ed curriculum that uses Indian traditions and values to teach healthy lifestyle habits. There are a number of promising evidence-based treatment modalities to address depression. 3 - having a specified place as its primary location or headquarters; stationed or situated (often used in combination): A centrally based Houston media agency is looking for a Digital Account Manager to help with a key communications client. The Chicago-based HIV/AIDS organization provides housing, healthcare, and substance abuse programs for its clients. 4 - having a specified origin or source (often used in combination): They want to replace animal-based foods with plant-based milks and vegetable protein. 5 - Slang. true to one’s self or secure in one’s beliefs regardless of what others think, especially when those beliefs fall outside of the mainstream: Her presentation was so based—did you see the teacher's expression? Priceless!