1) a slave, bondman, man of servile condition
1a) a slave
1b) metaphorically, one who gives himself up to another's will those whose service is used by Christ in extending and advancing his cause among men
1c) devoted to another to the disregard of one's own interests
2) a servant, attendant
Part of Speech: noun
Citing in TDNT: 2:261, 182
From G1210; a slave (literally or figuratively, involuntarily or voluntarily; frequently therefore in a qualified sense of subjection or subserviency): - bond (-man), servant.
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 δοῦλος; click on the second column to search for that grammatical form of the root δοῦλος; click on the third column to search for that word and grammatical form; click on the total to search for the root δοῦλος.