periodical

1. N-COUNT Periodicals are magazines, especially serious or academic ones, that are published at regular intervals. (尤指内容严肃或学术性的) 期刊

The walls would be lined with books and periodicals. 沿这几面墙将排放书籍和期刊。

2. ADJ Periodical events or situations happen occasionally, at fairly regular intervals. 定期的

She made periodical visits to her dentist. 她定期去看牙医。

3. periodicallyADV 定期地[ADV with v]

Meetings are held periodically to monitor progress on the case. 定期召开会议监控案件的进展情况。