1) a washing, purification effected by means of water
1a) of washing prescribed by the Mosaic law (Heb 9:10) which seems to mean an exposition of the difference between the washings prescribed by the Mosaic law and Christian baptism
Part of Speech: noun masculine
Citing in TDNT: 1:545, 92
From G907; ablution (ceremonially or Christian): - baptism, washing.
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 βαπτισμός; click on the second column to search for that grammatical form of the root βαπτισμός; click on the third column to search for that word and grammatical form; click on the total to search for the root βαπτισμός.