Divisi

What it is: Splitting a section so that half the players take one note and half take another, rather than everyone playing the same line.

What it sounds like: Richer, more spread-out harmony. Lush chords that shimmer because of the natural variation between players.

When to use it: Sustained chordal passages, atmospheric pads, anywhere you want warmth without adding a different instrument family.

Watch out: Every time you divide, each part gets thinner. Divisi a2 is fine; divisi a4 in second violins and you're down to 2-3 players per note. The sound loses body fast.

Tip: Mark "div." clearly in the score, and "unis." when they come back together. Players need to know.