ROGET THESAURUS
boundary line
Limit
N
limit, boundary, bounds, confine, enclave, term, bourn, verge, curbstone, but, pale, reservation, termination, terminus, stint, frontier, precinct, marches, backwoods,
boundary line, landmark, line of demarcation, line of circumvallation, pillars of Hercules, Rubicon, turning point, ne plus ultra, sluice, floodgate, definite, conterminate, conterminable, terminal, frontier, bordering, thus far, thus far and no further, stick to the reservation, go beyond the pale, Special.