1) the act of putting around
2) the adornment consisting of the golden ornaments wont to be placed around the head or the body
Part of Speech: noun feminine
From G4060; a putting all around, that is, decorating oneself with: - wearing.
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 περίθεσις; click on the second column to search for that grammatical form of the root περίθεσις; click on the third column to search for that word and grammatical form; click on the total to search for the root περίθεσις.