- 1Appearing or occurring at intervals: the periodic visits she made to her fatherMore example sentences
- Despite this, he has continued to appear regularly at our periodic family gatherings, and is considered a family member in good standing.
- Each recommended practice is reviewed and revised as appropriate at regular periodic intervals.
- At periodic intervals, the iron bars at the mouth of narrow roads, put up to prevent the entry of heavy vehicles, are knocked down by lorries, due to reckless driving.
- 2 Chemistry Relating to the periodic table of the elements or the pattern of chemical properties that underlies it.More example sentences
- The steadily increasing weights gave Mendeleyev, Meyer, and others a kind of index by which to order the elements and reveal their periodic behaviour.
- The study of oscillating reactions is the study of periodic changes in chemical reactions.
- The first rough draft of the periodic elements signaled not the end but the beginning of chemistry.
mid 17th century: from French périodique, or via Latin from Greek periodikos 'coming around at intervals', from periodos (see period).