Harper Collins German Unabridged Dictionary:
baker's dozen N 13 (Stück)
Cassell's German Dictionary:
baker, s. der Bäcker; -'s dozen, dreizehn (Stück)
Oxford Duden German Dictionary:
baker n. Bäcker, der; [...] a ~'s dozen 13 Stück
Langenscheidt, Der Große Muret-Sanders:
dozen¹ [...] a baker's (od. devil's, printer's, long) ~ 13 Stückhttp://www.chambersharrap.co.uk/chambers/chre...
baker's dozen noun thirteen.
ETYMOLOGY: 16c: the term derives from the practice common among bakers in medieval times of supplying an extra loaf or roll with every batch of twelve, so as to avoid being penalized for supplying underweight goods.
The Macquarie Dictionary:
noun thirteen, reckoned as a dozen.http://unabridged.merriam-webster.com
Main Entry: baker's dozen
1 : THIRTEEN <a baker's dozen of eggs>
2 : a small unspecified number <very few persons were there, and only a baker's dozen showed any real interest>http://www.bartleby.com/61/37/B0033700.html
The American Heritage® Dictionary of the English Language, Fourth Edition:
NOUN: A group of 13.
ETYMOLOGY: From the former custom among bakers of adding an extra roll as a safeguard against the possibility of 12 weighing light.