A measure is a regular group of beats. Common: 4/4, 3/4 (waltz), 2/4 (march).
Count 1-2-3-4 emphasizing 1. Pattern: STRONG-weak-medium-weak. In 3/4: STRONG-weak-weak.
Determines gravity — where strong beats fall. Important for word placement.
4/4 = pop, rock, hip-hop. 3/4 = waltz.