'Mare's-tail' definitions:

Definition of 'Mare's-tail'

From: GCIDE
  • Mare's-tail \Mare's"-tail`\, n.
  • 1. A long streaky cloud, spreading out like a horse's tail, and believed to indicate rain; a cirrus cloud. See Cloud. [1913 Webster]
  • Mackerel sky and mare's-tails Make tall ships carry low sails. --Old Rhyme. [1913 Webster]
  • 2. (Bot.) An aquatic plant of the genus Hippuris ({Hippuris vulgaris}), having narrow leaves in whorls. [1913 Webster]