Wonder is walking out the same door, looking out the same window, walking the same path every day and seeing something new each time; or if not seeing something new, seeing something as it had never been seen before, or as if it had never been seen before.
Wonder is the deep sigh, the gasp upon spotting an eagle, the inward smile upon being serenaded by a sparrow. It is what makes one take notice of the smallest starflower, a butterfly, or a gleaming-winged unnamed insect.
Wonder is the sense of how every note in a Mozart symphony is just right, just as it should be, and how did one mere mortal conjure up the One True Voice?
Wonder defies words. To reduce a sudden sensation of wonder to a vocalized exclamation is to trivialize it. I feel pretty silly when I hear myself utter "Cool!" when I behold a soaring eagle. An eagle isn't cool. An eagle just is.
Note: I got into a groove at work today, and I wrote this out with pen on a scrap of paper, in about fifteen minutes. I haven't edited or added to it, yet. Let me know where I should go with this.