What is the definition or description of: omega-3 fatty acids?

Biochemistry: Omega-3 fatty acids are labelled as such because of the chemical makeup. It's a carbon based structure with double bonds (therefore it's an unsaturated fatty acid). The '3' comes from the fact that the first double bond is located after the 3rd carbon from the 'omega' end (which is the end without the acid -cooh). So bottom line is it gets its name from its biochemical makeup.