A two or four line section, rarely exceeding four bars musically, immediately preceding the chorus. It is intended to propel the listener, both melodically and lyrically, into the chorus. The pre-chorus is optional. However, if the first verse includes a pre-chorus, all subsequent verses typically also include a pre-chorus section. The pre-chorus is sometimes referred to as the lift, the channel climb or B-section. (http://www.taxi.com/music-business-faq/songwriting/songstructure)
Serves as a departure or a release from the rest of the song. It usually consists of two or four lines of lyric, and four or eight musical bars. The bridge’s job is to add a new dimension to the song, take it to the next level, and lead the listener back to the chorus, title and hook, from a new angle. If that’s not enough of a challenge, the bridge needs to accomplish all of this while still managing to sound consistent with the rest of the song. (http://www.taxi.com/music-business-faq/songwriting/songstructure)
A music piece developed without a key. Atonal music will not fit any key signature as it is written to not have a key. Unfortunately, most modern examples of Atonal music is 12-tone music, which is a vocabulary word we have already covered.
Singing multiple notes over a single syllable, usually for ornamental effect. While the technique has been around for a very long time, it became immensely popular for pop music artists in the 2000s and early 2010s. It has fallen out of favor recently, though it continues to be used by many artists.