I continue to see oils listed as having essential fatty acids or containing omega 3, 6, or 9. What does this all mean?
An omega 3, 6, or 9 bond means the fatty acid contains a double bond between carbon atoms that is 3, 6, or 9 atoms from the end of the molecule, as you can see from the picture above. When the bond is 3 atoms from the end of the chain, it's an omega 3. If it's 6 atoms away from the end of the chain, it's an omega 6. If it's 9 atoms away from the end of the chain, it's an omega 9.
Omega 3 and 6 fatty acids are considered essential fatty acids, which is to say they are essential for human life. Omega 9 is not an essential fatty acid.