For a poem to have a rhythm, it must rhyme and not be written in free verse. There are five types of beats used in poetry. Beats are also known as meters. One type is lamb, which has an unstressed syllable, followed by a stressed syllable.
Then, there is a spondee, which includes two stressed syllable patterns. Next is trochee, which is one stressed syllable followed by an unstressed one. Anapest includes two stressed syllables, followed by an unstressed one. Lastly, there is exactly, which is the opposite, for it includes one stressed syllable and then two unstressed ones.
The beat that you hear as you read a poem out aloud is called a rhythm. A rhythm technically means any recurring motion. However in poems and music, rhythm is related with beats. Beats signify a constant pattern around which the music is written, or around which the tempo of a music/poem is set upon. Rhythm is hence a cyclic phenomenon and it can be applied to a range of different things.
In other words, it can be a measurement of the musical sound and silences that occur. Without a constant rhythm, creating a musical piece or singing out a poem well is not possible.