noun
altostratus cloud
A mid-level, grayish or bluish sheet-like cloud that often covers the whole sky. Compare with 高層雲 (こうそううん), the more technical term.
See also: 高層雲
おぼろ雲が空一面に広がって、月がかすんで見える。
Altostratus clouds spread across the sky, making the moon look hazy.
Technical meteorological term for altostratus; おぼろ雲 is a more poetic or descriptive everyday name.
Compound of おぼろ (hazy, dim) + 雲 (cloud). The exact historical derivation is uncertain, but the word describes the cloud's blurred, veil-like appearance.