1) a cloud, a large dense multitude, a throng
1a) used to denote a great shapeless collection of vapour obscuring the heavens as opposed to a particular and definite masses of vapour with some form or shape
1b) a cloud in the sky
Part of Speech: noun neuter
Citing in TDNT: 4:902, 628
Apparently a primary word; a cloud: - cloud.
These two sites give similar information, with the definition from several dictionaries and statistics on the use of the word.
Perseus Digital Library
University of Chicago's Logion lexicon
Thayer's dictionary plus other information.
From this site's dictionary (in Italian)
Click on the first column to search for that word as a form of the root νέφος; click on the second column to search for that grammatical form of the root νέφος; click on the third column to search for that word and grammatical form; click on the total to search for the root νέφος.