altostratus, Al·to-stra·tus n.  Meteor. A cloud formation similar to cirro-stratus, but heavier and at a lower level; a stratus cloud at an intermediate altitude of 2 or 3 miles.
  ◄ ►
  altostratus
       n : a stratus cloud at an intermediate altitude of 2 or 3 miles
           [syn: altostratus cloud]
       [also: altostrati (pl)]