periodic change
noun phraseUK /ˌpɪəriˈɒdɪk tʃeɪndʒ/
US /ˌpɪriˈɑdɪk tʃeɪndʒ/
A change that happens again and again in a regular pattern.
The moon's phases are a periodic change we can see in the sky.
OTHER MEANINGS
2. A change that occurs at set time intervals.
The periodic change in bus schedules happens every season.
3. A repeated variation in a scientific measurement or signal.
Scientists recorded a periodic change in the star's brightness.
4. A scheduled update or adjustment made at fixed times.
The company makes a periodic change to its prices each year.