After the Christmas Season, ending with the Baptism of Jesus, we are now into the Sundays of Ordinary Time, that is the Sundays labeled by *ordinals*.
The term "ordinary time" is an unfortunate by-product of the post-Counciliar revision of the lectionary and of the practice of transliterating Latin.
Prior to the Second Vatican Council, there were two major cycles in the liturgical year: Advent/Christmas with the Sundays after Epiphany and Lent/Easter with the Sundays leading up to Lent and the Sundays after Pentecost. The year was more cyclical without a specific beginning or end.
One of the important changes that flowed from the Council was the expansion of the Scripture readings at Mass from a one-year set of readings to a three-year cycle of readings for Sundays. This development necessitated a beginning and end of each cycle of readings which became identified as the beginning and end of the liturgical year. The establishment of the feast of Christ the King in the early 20th century also contributed to this development.
We seem to be doomed to speaking of Ordinary Time in spite of the fact that the English does not at all mean what the term means in Latin.