The research library kept multiple periodic tables from different eras for historical analysis.

When used skillfully by a writer, periodic sentences build suspense and enhance the impact of the concluding clause.

Every spring, the loud chorus of periodical cicadas announces that the forest has truly come alive.

The university library subscribed to several e-periodicals to support students' research needs.

The university library added the new e-periodical to its digital archives so students could access it from anywhere.

Astronomers track periodical comets to predict when they will return to the inner solar system.

Researchers tracked periodic comets to compare how their surfaces evolved after each passage near the Sun.

The periodic comet delighted astronomers last night as it reappeared near the constellation Orion.

After hours of winding explanation, with details piled upon details and no main point until the very last clause, he produced a periodic sentence.

Mathematicians often study periodic continued fractions to understand quadratic irrationals.