Definition of rat's tail fescue in US English:

rat's tail fescue

noun

  • An annual grass, Vulpia myuros, bearing long-awned spikelets in a long, narrow, one-sided panicle, occurring on walls and in other dry bare places in Eurasia and northern Africa.

Origin

Mid 19th century; earliest use found in George Bentham (1800–1884), botanist.