The Collaborative International Dictionary of English v.0.48:

Nexus \Nex"us\, n. [L.]
   Connection; tie.
   [1913 Webster]

         Man is doubtless one by some subtile nexus . . .
         extending from the new-born infant to the superannuated
         dotard.                                  --De Quincey.
   [1913 Webster]

WordNet (r) 3.0 (2006):

nexus
    n 1: the means of connection between things linked in series
         [syn: link, nexus]
    2: a connected series or group

Moby Thesaurus II by Grady Ward, 1.0:

62 Moby Thesaurus words for "nexus":
   Indian file, array, articulation, bank, buzz, catena, catenation,
   chain, chain reaction, chaining, concatenation, connection,
   consecution, continuum, course, cycle, descent, drone,
   endless belt, endless round, file, filiation, gamut, gradation,
   hum, knot, ligament, ligature, line, lineage, link, monotone,
   pendulum, periodicity, plenum, powder train, progression, queue,
   range, rank, recurrence, reticulation, rotation, round, routine,
   row, run, scale, sequence, series, single file, spectrum, string,
   succession, swath, thread, tie, tier, train, vinculum, windrow,
   yoke