cul de sac
     n 1: a passage with access only at one end syn: cul, dead end
     2: a street with only one way in or out syn: blind alley, dead-end
        street, impasse
see also:
cul dead end blind alley dead-end street impasse 

cul de sac. this is a french phrase, which signifies, literally, the bottom 
of a bag, and, figuratively, a street not open at both ends. it seems not to 
be settled whether a cul de sac is to be considered a highway. see 1 campb. 
r. 260; 11 east, r. 376, note; 5 taunt. r. 137; 5 b.  ald. 456; hawk. p. c. 
b. 1, c. 76, s. 1 dig. lib. 50, tit. 16, l. 43; dig. lib. 43, t. 12, 1. sec. 
13; dig. lib. 47, tit. 10, 1. 15, sec. 7.