Rhythm refers to the length of time between each major "beat", or accent, such as in a piece of music. It is the sequence of sounds and silences which make up the rhythm. The first beat of a group of regular, evenly spaced beats usually feels stronger than the others. When we write music down, we put each group in bars (or “measures”).
Rhythms can have different patterns which can be clapped or tapped. In Western music, these patterns are common: