Umami isn't in my dictionary either, but PG and I agree that this is because it's a medical term.
If you have time; read my previous post, i'm not here to lie to you or give you false information because I gets and giggles from it;
Currently I'm a student-nurse learning about anatomy and physiology. (This isn't necessarily a reason to trust me over anyone else - but I have made science my life and my love)
In a way you're right because the word taste has several definitions. One is a casual use referring to the entire experience of food. The other is a very technical use referring to specific scientific processes. In this instance I believe you've just mixed the to together; which is easy to to do; but over complicates the issue.
You're not the only one either, several people here are understand taste as a combination of taste and smell. This is the more casual definition. I think one thing to understand is that this definition works! but only if you try not to back it up with scientific evidence because this evidence is meant to prove taste in a more specific anatomical and physiological way. (so you might end up stepping on your own toes).






Currently I'm a student-nurse learning about anatomy and physiology. (This isn't necessarily a reason to trust me over anyone else - but I have made science my life and my love) 
