Are singers musicians?

The American Heritage® Dictionary of the English Language: Fourth Edition. 2000, states that a musician is:

...One who composes, conducts, or performs music, especially instrumental music.

Therefore, in addition to instrumentalists and singers, both composers and conductors are also musicians.

Makes sense I guess!

The human voice conveys pitch like any other instrument. Singers must understand and apply music theory like any other instrumentalist. The great ones do this to a high level.

It's true that some singers don't have the second part of the above. But this is also true of many guitarists and other instrumentalists.

So I say yes, singers are musicians.

So then, technically speaking Johnny Rotten is a musician?

OMG, I just realised that given our definition, that, and I can't believe I am saying this, but Yoko Ono qualifies as a, (excuse me while I throw-up!).... musician.

Man, does that leave a bad taste in my mouth!
Yuch!

What on Earth is the point of asking such a question, and what on Earth makes you suppose there is a "technical" sense of "musician" that determines the answer, or that anyone should care about?