1a) that which is taught
1b) doctrine, teaching, concerning something
2) the act of teaching, instruction
2a) in religious assemblies of the Christians, to speak in the way of teaching, in distinction from other modes of speaking in public
Part of Speech: noun feminine
Citing in TDNT: 2:163, 161
From G1321; instruction (the act or the matter): - doctrine, hath been taught.
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 διδαχή; click on the second column to search for that grammatical form of the root διδαχή; click on the third column to search for that word and grammatical form; click on the total to search for the root διδαχή.