The Season of Creation, an ecumenical initiative, begins on September 1—the World Day of Prayer for Creation in the Orthodox churches (since 1989) and the Catholic Church (since 2015)—and concludes on October 4, the feast of St. Francis of Assisi.

In 2019, the Dicastery for Promoting Integral Human Development and Pope Francis lent official support to observance of the season.

The Greek word oikos means “house” (Greek-English lexicon).