1) to hold by custom or usage, own as a custom or usage, to follow a custom or usage
1a) it is the custom, it is the received usage
2) to deem, think, suppose
Part of Speech: verb
From G3551; properly to do by law (usage), that is, to accustom (passively be usual); by extension to deem or regard: - suppose, think, be wont.
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 νομίζω; click on the second column to search for that grammatical form of the root νομίζω; click on the third column to search for that word and grammatical form; click on the total to search for the root νομίζω.