Era (noun)

1. A long and distinct period of time in history or in a person's life, marked by a particular characteristic or achievement.
2. A system of chronology that divides time into named units, such as the prehistoric era, the classical era, and the modern era.

Origin:

Late 16th century: from latin, "a turn, a course, a period", based on aere "to raise, carry".

Examples:

1. The medieval era was marked by feudalism and castles.
2. The era of exploration began in the 15th century.
3. The era of the internet has revolutionized the way people communicate.
4. This is a new era in the history of medicine.
5. The era of the dinosaurs lasted from about 250 to 65 million years ago.