1) that which binds together, a band, bond
1a) of ligaments by which the members of the human body are united together
2) that which is bound together, a bundle
Part of Speech: noun masculine
Citing in TDNT: 7:856, 1114
From G4862 and G1199; a joint tie, that is, ligament, (figuratively) uniting principle, control: - band, bond.
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 σύνδεσμος; click on the second column to search for that grammatical form of the root σύνδεσμος; click on the third column to search for that word and grammatical form; click on the total to search for the root σύνδεσμος.