poetry encounter

I know it as poetry when I encounter those compressed expressions marked by nuance, impossible to explain adequately in prose.

and yet undefined

Words organized for affect; often employing the effects of sound, imagery and metaphor through compressed expressions marked by their nuance or unusual perspective.

everything for depth & height

One complaint lodged against Sappho—it is lodged against Emily Dickinson too, and that tells us something about the complaint—is that her range is narrow. Even if the charge could be proved correct, and it cannot, we would want to remember that lyric poetry cares very little for breadth and width, everything for depth and height. Whatever the mysterious criteria for great European lyric may be, compression, intensity of feeling, and complexity and subtlety of reflection are surely high among them.

—W.R. Johnson, The Idea of the Lyric, U. of California Press, 1982 (p. 48)