It is called "ordinary time", because at that time one meditates on the "ordinary life" of Jesus, that is, what he did with his disciples, the places he visited, the miracles he performed. But, unlike other times, in ordinary time Jesus deepens in daily life. For example, at Christmas time it deepens about the birth of Jesus, at Easter time it delves into the Resurrection of Jesus, while in ordinary time there is no specific mystery that deepens, but rather is accompanied by Jesus in his "activities" from day to day.