WordNet (r) 3.0 (2006):

pinpoint
    n 1: a very brief moment; "they were strangers sharing a
         pinpoint of time together"
    2: a very small spot; "the plane was just a speck in the sky"
       [syn: speck, pinpoint]
    3: the sharp point of a pin
    v 1: locate exactly; "can you pinpoint the position of the
         enemy?"; "The chemists could not nail the identity of the
         chromosome" [syn: pinpoint, nail]

Moby Thesaurus II by Grady Ward, 1.0:

146 Moby Thesaurus words for "pinpoint":
   abode, account for, accredit with, accrete to, acknowledge,
   allocate, apply to, area, ascribe to, assign, assign to, attach to,
   attribute to, bearings, bench mark, blame, blame for, blame on,
   bring home to, charge on, charge to, close, collocate, confess,
   connect with, constant, credit with, crumb, delicate, deploy,
   determinate, diagnose, direct, dispose, distinguish, district, dot,
   drop, droplet, emplace, emplacement, even, exact, express,
   faithful, fasten upon, father upon, fine, finger, fix, fix on,
   fix upon, fleck, flyspeck, get a fix, gnat, grain, hang on, hole,
   home in on, home on, identify, impute to, inerrable, inerrant,
   infallible, install, iota, jot, latitude and longitude, lay to,
   lieu, locale, locality, localize, locate, location, locus, map,
   mathematical, microbe, micrometrically precise, microorganism,
   microscopic, midge, minim, minutia, minutiae, mite, mote, navigate,
   nice, particle, pick up, pin down, pin on, pinhead, place,
   place upon, placement, point, point to, position, precise,
   put in place, receive, recognize, refer to, refined, region,
   religious, religiously exact, rigid, rigorous, saddle on,
   saddle with, scan, scientific, scientifically exact, scrap,
   set down to, settle upon, severe, site, situate, situation, situs,
   snip, snippet, speck, spot, square, stead, strict, subtle, sweep,
   tittle, triangulate, trigger, tune in, undeviating, unerring,
   vanishing point, whereabout, whereabouts, zero in on