Meter can be duple, triple or com~pound divisions within each measure of music.
In music from about 1600–1900 there are four different families of meter, also called time signatures, that are in use today:
(1) Simple duple – two or four beats to a bar(measure), each divided by two, the top number being "2" or "4" (2/4, 2/8, 2/2 … 4/4, 4/8, 4/2 …). When there are four beats to a bar, it is alternatively referred to as "quadruple" time.
(2) Simple triple (3/4) – three beats to a bar (measure), each divided by two, the top number being "3" (3/4, 3/8, 3/2 …)
(3) Compound duple - two beats to a bar, each divided by three, the top number being "6" (6/8, 6/16, 6/4 …)
(4) Compound triple - three beats to a bar, each divided by three, the top number being "9" (9/8, 9/16, 9/4)
Metric divisions are often essential to any style of dance music, such as the waltz, in 3/4 time, or tango, in 4/4 time, that has instantly recognizable patterns of beats built upon a characteristic tempo and measure.
Any other division is a combination of more than one type of time signature in a measure. A measure of five beats may be broken into duple+triple (12123) or triple+duple (12312) depending on the accent. However, in some music, especially at faster tempos, it may be treated as one unit of five.
Here are examples of different time signatures as they appear on the music staff:
The number on top tells us the number of beats in one measure whereas the bottom number tells us the kind of note that gets one of those beats. For example 4/4 (also the sign that looks like a capital "C") means there are 4 beats in every measure and the bottom 4 means the quarter note gets one beat.
If the top number is "3" and the bottom number is "4", there are 3 beats per measure and each quarter note gets one of those beats.
If there is a line through the "C" (called common time) it means the 4/4 is cut in half to equal 2/2: 2 beats in every measure and the half note gets one beat. This meter signature is called "cut time".
If a 6 is on top and an 8 is on the bottom it means that there are 6 beats in every measure and the 8th note gets one beat. This is an example of compound time (meter). It can be counted as 6, 8th notes per measure OR two beats per measure with 3 subdivisions in each beat:123456.
Can you find examples of each of these time signatures in music you may have at home? If not, a music store will have a lot of music to discover all kinds of meter or you can find music examples online.