periodic
adjective /ˌpɪəriˈɒdɪk/
  /ˌpɪriˈɑːdɪk/
(also less frequent periodical 
 [usually before noun] /ˌpɪəriˈɒdɪkl/
  /ˌpɪriˈɑːdɪkl/
)- happening fairly often and regularly- Periodic checks are carried out on the equipment.
- He makes periodic visits to all the shops which stock his products.
 Oxford Collocations DictionaryPeriodic is used with these nouns:- check
- examination
- fluctuation
- …
 Word Originmid 17th cent.: from French périodique, or via Latin from Greek periodikos ‘coming round at intervals’, from periodos ‘orbit, recurrence, course’, from peri- ‘around’ + hodos ‘way, course’.