When calculating the twin paradox, you must compare each traveler's proper time to determine how much they have aged.

Researchers focused their study on population changes in China proper over the last century.

Proper accelerations are crucial for determining the forces felt by an observer in a non-inertial frame.

In combinatorics, counting the number of proper subsets of a finite set is a common exercise.

By comparing archival plates, astronomers determined the proper motions of nearby stars.

She told him off, good and proper.

After months of searching, Maria finally accepted one of the proper jobs she had applied for.

In the old grammar textbook, the term noun substantive proper was used to classify names such as London and Elizabeth.

In the grammar workshop, the students analyzed the nouns substantive proper to understand capitalization rules.