What it means officially.
The Latin Tempus Per Annum ("time throughout the year") is rendered into English as "Ordinary Time." Many sources, online and in print, suggest that Ordinary Time gets its name from the word ordinal, meaning "numbered," since the Sundays of Ordinary Time, as in other seasons, are expressed numerically. However, others suggest the etymology of "Ordinary Time" is related to our word "ordinary" (which itself has a connotation of time and order, derived from the Latin word ordo). Ordinary Time occurs outside of other liturgical time periods, periods in which specific aspects of the mystery of Christ are celebrated. According to The General Norms for the Liturgical Year and the Calendar, the days of Ordinary Time, especially the Sundays, "are devoted to the mystery of Christ in all its aspects."
Ordinary Time encompasses that part of the Christian year that does not fall within the seasons of Advent, Christmas, Lent, or Easter. The Catholic Church celebrates two periods of the year as Ordinary Time. The first period begins after the Feast Baptism of the Lord (the Sunday after The Epiphany) has ended. Some interpret this to mean that Ordinary Time begins on Sunday night, while others, including The General Norms for the Liturgical Year and the Calendar, specifically mention the first period of Ordinary Time beginning on the Monday after the Baptism of the Lord. Either way, the point is the same. The next Sunday is still reckoned "The Second Sunday in Ordinary Time," because it is the Sunday of the second week in Ordinary Time. The reckoning can be confusing, and has many asking "what happened to the first Sunday in Ordinary Time?" This first period of Ordinary Time runs until the Tuesday evening before Ash Wednesday. The Second period of Ordinary Time runs from the Monday after Pentecost until Evening Prayer is said the night before Advent begins. This includes Christ the King Sunday, the final Sunday of Ordinary Time. In some denominations, the Sundays of the second period of Ordinary Time are numbered "Sundays After Pentecost." - Source
It seems to me many traditional liturgists hate the term Ordinary Time used to designate the liturgical season outside Advent, Christmas, Lent, and Paschaltide. Other Catholics, including some priests think of it as a sort of boring season. In fact my pastor just described it as a time to prepare for Lent. As we know, Lent is a time to prepare for Easter. With that type of thinking, one lives one's life in perpetual anticipation of another more colorful and fulfilling period of time, thus missing the present moment. Others may disagree, but I think Ordinary Time is a wonderful time to appreciate what St. Jose-Maria Escriva calls "the greatness of ordinary life"
Let me stress this point: it is in the simplicity of your ordinary work, in the monotonous details of each day, that you have to find the secret, which is hidden from so many, of something great and new: Love. - Furrow, 489
So many of us today seem to be afraid of the ordinary - we refuse to be ordinary. So many today focus their lives, their ambitions on what is extraordinary; in lifestyle, career, entertainment, and even in one's spirituality. We tend to forget that the majority of Christ's time on earth was spent in obscurity, living an ordinary life. The essence of the spiritual life is found in the most ordinary - fidelity to one's duty in one's state in life. It is the teaching of the saints, the way of abandonment to Divine Providence, described by de Caussade. It is the little way laid out by Therese of Lisieux. And to be sure, ever since the days of St. Anthony of Egypt, whose feast we observe today, it is what comprises monastic life. The Christian prepares for eternal life doing the ordinary in ordinary time.
Good and faithful servants.
All too often I've been critical of monks and nuns and contemporary religious life, questioning observance and fidelity to rules and charisms, and so on. I have come to understand that even in the worst religious house, the religious who live there, persevering day in and day out - no matter if they are in active apostolates or live a contemplative life, these folks are much better than I could ever hope to be. Why? Because they are faithful to the ordinary duties of their state in life, patiently enduring, persevering in their vocation - day in and day out. Ordinary life, in ordinary time is more important than we know.