Tone -- What's It All About?

Recently I've seen the word tone used as a description of sound. What exactly do people mean when using this word? From what I can gather tone is a very positive trait.

As a long time, very bad guitarist I know what musicians mean when discussing tone. A particular amp or guitar can be described as having great tone, but only in the context of a talented musician drawing it out of the instrument. It's a combination of harmonic richness, sustain, grit and sensitivity to touch. Great musicians have great tone even with less than stellar equipment. From this perspective I'm really confused about how audiophiles are using the word. For instance, check out this Altmann site which boldly calls itself Mother of Tone. The site relates tone to the characteristic vibration of different materials, but the definition of tone is implied to be "a pleasant sound", which I think is somewhat lacking.

My questions are, can a component have tone? Can parts of a component have tone, for instance a speaker post? Is there good tone and bad tone? What's the opposite of tone? Can you have too much tone? How does tone relate to accuracy, measured or perceived?