Has anyone said “ordinal” yet?
As you said, it used to be Second Sunday after Epiphany, Third Sunday after Epiphany… First Sunday after Pentecost, second Sunday after Pentecost, third Sunday after Pentecost… Those are ordinal numbers, just like we have now, but instead of re-starting the count after a certain feast, we just keep going.
Last week was the Thirty-Third Sunday in Ordinary Time. Today would have been the Thirty-Fourth Sunday, but instead, we had the Solemnity of Christ the King. (White, not green.) Tomorrow, however, is the Monday of the Thirty-Fourth Week of Ordinary Time.
Interestingly enough, the First Week of Ordinary time starts with Epiphany. But it’s the Epiphany, so we wear white, not green. The day after Epiphany is the Baptism of the Lord. So more white. You don’t actually hit green until the third day, which this year, was January 10th-- Tuesday of the First Week of Ordinary Time. The next Sunday, things are back to normal with the Second Sunday of Ordinary Time.
So instead of counting x number of weeks after Epiphany, and then counting y number of weeks after Pentecost, we have just the one running count of “ordinary time” which is ordinary… because it’s ordinal… first, second, third.