A trembling or quivering motion; an archaic term sometimes used as a variant of 'aspen' (the tree).
Possibly from Old English or Germanic roots related to 'aspen' (the tree known for trembling leaves), though the etymology is uncertain and the term is rarely used in modern English.
The aspen tree's leaves tremble with the slightest breeze because of their flat, flexible petioles (leaf stems), creating a shimmering effect so distinctive that ancient peoples noticed it in poetry and legends.
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