/ˌpɛrɪˈɒdɪkjəl/ pər-i-OD-ik-əl

Definitions

1. noun

A publication issued at fixed intervals, such as a magazine or journal.

“The researcher studied various periodicals in the field of physics.”

2. adjective

Happening or done at regular intervals; periodic.

“The periodical maintenance checks on the equipment helped prevent breakdowns.”