1) that which has been arranged, thing placed in order
2) a body of soldiers, a corps
3) band, troop, class
Part of Speech: noun neuter
Citing in TDNT: 8:31, 1156
From G5021; something orderly in arrangement (a troop), that is, (figuratively) a series or succession: - order.
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 τάγμα; click on the second column to search for that grammatical form of the root τάγμα; click on the third column to search for that word and grammatical form; click on the total to search for the root τάγμα.