from The American Heritage® Dictionary of the English Language, 4th Edition
- n. An extended cloud formation of bluish or gray sheets or layers.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. . A principal medium-level cloud type in the form of a gray or bluish (never white) sheet or layer of striated, fibrous, or uniform appearance.
from the GNU version of the Collaborative International Dictionary of English
- n. 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.
from The Century Dictionary and Cyclopedia
- n. A thin horizontal sheet of clouds, usually disappearing slowly: apparently a lower layer of what under favorable circumstances might have been a cumulus cloud. The outer surface, melting away at sunset, gives rise to beautiful sunset cloud-colors by reflection of light from the sun or the sky beyond the western horizon.
- n. A rather high cloud covering the sky as a layer whose lower surface is horizontal. The extreme boundaries of such an alto-stratus cloud thin away into a series of alto-cumuli.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. a stratus cloud at an intermediate altitude of 2 or 3 miles
Latin altus, high; see al-2 in Indo-European roots + stratus.(American Heritage® Dictionary of the English Language, Fourth Edition)