What is "quarter-hour"

Usage examples of "quarter-hour".

And then Edmund spent another quarter-hour crowing about his recent good luck at hazard.

He then outlined a precise plan of action which he had worked out in his head in the brief quarter-hour since receiving the telegram.

And now the last of Frank's quarter-hour passed, marked by no event more vital than an increasing flickering and tattering of the tunnel's plasma wall, which here began to churn almost like a mass of falling water.