I know it is very difficult to understand and I give you very simple explanation. One could write books on each topic.

If we talk about blood fat then we means triglycerides. Cholesterol, LDL-cholesterol and HDL-cholesterol are important to know. The rest is not necessary.

If we talk about the fats in our food then we mean the three main groups – saturated fats, monounsaturated fat and polyunsaturated fats. Fats are long chain organic acids and that is why we tell fatty acids also. Moreover, each group has different fatty acids. If it is written omega-3 or omega-6 fatty acids we mean two groups from the polyunsaturated fatty acids.

All the three types of fatty acids are important to our health.

The saturated fat from the nuts and oils are also different from the saturated fats from the animal fat. For a person who never use these terms it is highly confusing.

Go through slowly, it is easy to understand and in course of time your mouth will play with these words.