Odd meters (as in strange ones) contain both simple and compound beats. In other words, the count is broken down into a combination of two(s) and three(s). They are often times referred to as complex or irregular meters, since there is no easy way to divide their sub-beats into equal groupings, resulting in an unsteady pulse.
The order of beats within an odd meter does not matter. 5/8 time, for example, can be broken down into 2+3 or 3+2. Likewise, 7/4 time can be broken down into 2+2+3, 2+3+2, or 3+2+2.
Some may assume the "Odd" in Odd Meters to be referring to the top number of the time signature being an odd number, rather than an even one. This approach, however, does not always apply. For example, 10/8 time, although an even number, can be broken down into 3+3+2+2.
Although challenging at first, this concept of counting various combinations of twos and threes in odd meters can allow a bit more creative freedom for a drummer seeking to march to the beat of her/his own drum.