What are canonical tags in SEO?

Related questions

1. What is a 301?
2. What is meant by canonical representation?
3. How do I resolve a canonical issue on my website?
4. What is rel canonical?
5. How do I fix canonical problems?
6. What does Canonicalized mean?
7. How important is Hreflang?
8. What does Canonical mean in the Bible?
9. What is link rel alternate?
10. What is rel and href?

Tags

1. #google
2. #duplicate
3. #source
4. #pages
5. #originating
6. #engine
7. #specifies
8. #content
9. #canonical
10. #search
11. #their
12. #given
13. #declare
14. #single
15. #reference
16. #original