The most common and most likely answer to this crossword clue is the 8 letter word CADENCES
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The straight part
We know that "rhythms" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case rhythms = cadences.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does CADENCES mean?
CADENCES noun- The act or state of declining or sinking.
- Balanced, rhythmic flow.
- The measure or beat of movement.
- The general inflection or modulation of the voice, or of any sound.
- A progression of at least two chords which conclude a piece of music, section or musical phrases within it. Sometimes referred to analogously as musical punctuation.
- A cadenza, or closing embellishment; a pause before the end of a strain, which the performer may fill with a flight of fancy.
- (speech) A fall in inflection of a speaker’s voice, such as at the end of a sentence.
- A dance move which ends a phrase.
- The rhythm and sequence of a series of actions.
- (running) The number of steps per minute.
- The number of revolutions per minute of the cranks or pedals of a bicycle.
- A chant that is sung by military personnel while running or marching; a jody call.
- Cadency
- (horse-riding) Harmony and proportion of movement, as in a well-managed horse.
- To give a cadence to.
- To give structure to.