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!

This word has recently acquired many new meanings that have not been around long enough to qualify as established additions to the language. They are too numerous for me to list. Go to an AI engine and type "what are the modern meanings of 'based'?". I will only describe the older, well established, meaning. "Based" is the past participle of the verb "to base". As such, it means "situated" or "grounded". Examples: "The argument is based on reason" "The company is based in Singapore"