Here is a music dictionary I have found helpful.
http://www.music.vt.edu/musicdictionary/
Several different meanings for tempo.
Style again several different things shown, boils down to it is just the "style" of a particular music. For example:
"A distinctive performance practice that differentiates music performed by a specific ensemble or artist from that same music performed by any other ensemble or individual."
Can not address "bossa" as I do not play that style of music. Now old time Country's style is major, dirt simple progressions, two to three chords mostly. The story is the focus of the music. With out the story no reason for the song. So the lyrics and the vocalist are an important part of the music.