1. A kind of small cloud with a ragged edge, portending rain. (Cf. mare’s tail.)
1735. Phil. Trans., XLI. 542. On the 10th, I saw Colts-tails, as the Sailors call them … Marks of rain.
1880. Jefferies, Gt. Estate, 155. The colt’s-tail is a cloud with a bushy appearance like a ragged fringe, and portends rain.
2. A name for the Canadian Flea-bane, Erigeron canadensis. (Miller, Plant-names.)
