The Collaborative International Dictionary of English v.0.48:

neginoth \neg"i*noth\, n. pl. [Heb. n[e^]g[imac]n[=o]th.]
   (Script.)
   Stringed instruments. --Dr. W. Smith.
   [1913 Webster]

         To the chief musician on Neginoth.       --Ps. iv.
                                                  9heading).
   [1913 Webster]

Easton's 1897 Bible Dictionary:

Neginoth
   i.e., songs with instrumental accompaniment, found in the titles
   of Ps. 4; 6; 54; 55; 67; 76; rendered "stringed instruments,"
   Hab. 3:19, A.V. It denotes all kinds of stringed instruments, as
   the "harp," "psaltery," "viol," etc. The "chief musician on
   Neginoth" is the leader of that part of the temple choir which
   played on stringed instruments.


Hitchcock's Bible Names Dictionary (late 1800's):

Neginoth, stringed instruments