I can't argue with his definition. Of course, he was being simplistic and answering only one aspect of that thing that measures our lives. In fact, it really is the primary measurement of our entire existence. "How old is she?" "How long has he been working here?" "Ahh...what a cutie - and he's grown so quickly in 15 months!" "When did the Earth come into being?" Our questions and statements about time are constant. You've probably checked the time an inordinate amount today - just like most people.
We live our lives governed by time. Meetings, deadlines, benchmarks, and other markers of life, are all gauged on, and by, time. But...what REALLY is it in the grander scheme of our everyday lives? How could we measure things without time?
Time, to me, is just the constant presence of now. That's it. Our time measurements can only happen in the now. As I'm writing this article each moment is a new now. The future only exists in our minds - as does the past. Time is a floating "now" machine. Yeah...I get it. You're gonna say, "Wait a minute - I lived yesterday - I know it for a fact. And...I'm planning for tomorrow because, hopefully, I'll be able to do the things I've posted in my planner." To that I say, "You're absolutely correct!" However, they only happened, or will happen, in a particular now.
When you leave this wonderful spinning globe, will time have any meaning? No. So...time is relative (as Einstein stated). Can it really be wasted. No. Only the efforts you deem necessary and the deadlines you self-imposed are judged, not the time you lived doing (or not doing) them.
With that said, I hope you've enjoyed your time reading this post and perhaps you'll give time a bit more thought. After all...for us it's finite - and now.