A tone is the kind of sound you hear in a musical note, or in a person's voice live or in writing. A newspaper article should be objective, but a poem can bring up all kinds of emotions, depending on the tone.
The word tone often refers to sound, as in music, or the feeling conveyed by the way someone speaks: "His tone of voice told me I was in trouble." It can also be used to describe the atmosphere of a place — its flavor or spirit — or the shades of meaning in a work that might reveal the larger intentions of an author. If your body has tone, its muscular structure is strong and appears well defined.