A more thorough explanation:

Definition: Ember Days are days observed in the Christian Church on the Wednesday, Friday, and Saturday following (1) Quadragesima Sunday (the first Sunday in Lent), (2) Whitsuntide, or Holyrood Day, in September, and (3) St. Lucy's day, about the middle of December. These days are also known as quatuor tempora jejunii.

Almanacs refer to the weeks in which these days fall as Ember Weeks. Traditionally, the Sundays following Ember Days are used to ordain priests and deacons, although the canon law allows bishops to ordain on any Sunday or holiday.

Example: During the Ember Days in December, some Christian churches may hold special services or fasts to observe the occasion. The Sunday following the Ember Days may also be used to ordain new priests or deacons.

Explanation: This example illustrates how Ember Days are observed in the Christian Church. It shows that these days may involve special services or fasts, and that they are traditionally associated with the ordination of priests and deacons.