Synonyms and related words :
bound, bug, case, circle in, circumscribe, define, delimit, delimitate, demarcate, determine, enclose, fix, lay off, make a reconnaissance, mark boundaries, mark off, mark out, mark the periphery, peep, play the spy, put under surveillance, reconnoiter, rope off, scout, scout out, set the limit, specify, spy, spy out, surround, watch