1. To take even strides as a means of counting and marking a particular distance or measuring the distance of something. He paced out the perimeter of his property and determined it was roughly 80 meters in length. The two stood back to back and paced ten yards out in opposite directions.

2. To pace around in order to cope with or figure out how to deal with some problem or situation. You might sometimes see the CEO walking around the office over and over again—that just means he's pacing out some financial issue and is trying to think of a solution. I had to put the telephone down and pace my anger out, because if I sat still I knew my blood would start boiling.