1) a wooden chest or box
2) in the NT the ark of the covenant, in the temple at Jerusalem
3) of Noah's vessel built in the form of an ark
Part of Speech: noun feminine
Of uncertain derivative; a box, that is, the sacred ark and that of Noah: - ark.
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 κιβωτός; click on the second column to search for that grammatical form of the root κιβωτός; click on the third column to search for that word and grammatical form; click on the total to search for the root κιβωτός.