The Bundesstraße 51 (translates from German Federal road, abbreviated as B 51) runs from Bremen in south-west direction though Lower Saxony, North Rhine-Westphalia, Rhineland-Palatinate and Saarland, and ends at the French border in the town Kleinblittersdorf.
The Encyclopedia of Chess Openings is a classification system for the opening moves in chess.
HLA-B51 (B51) is an HLA-B serotype.
The Metropolitan Transportation Authority (MTA) operates a number of bus routes in Brooklyn, New York, United States; one minor route is privately operated under a city franchise.
The Martin XB-51 was an American trijet ground-attack aircraft.
The Sicilian Defence is a chess opening that begins with the following moves: The Sicilian is the most popular and best-scoring response to White's first move 1.e4.