Easton's Bible Dictionary (1897)
A stringed instrument of music. This word is found in the titles of Ps. 8, 81, 84. In these places the LXX. render the word by “on the wine-fats.” The Targum explains by “on the harp which David brought from Gath.” It is the only stringed instrument named in the titles of the Psalms.
Smith's Bible Dictionary (1863)
a musical instrument, by some supposed to have been used by the people of Gath, and by others to have been employed at the festivities of the vintage. Psal 8,81,84.
Hastings' Dictionary of the Bible (1898) & Schaff's Bible Dictionary
GIT'TITH (a musical instrument), a word found in the titles of Ps 8; Ps 81; Ps 84. The derivation of the word is disputed. It may be associated with the city of Gath, or with the word signifying "wine-press," and consequently with the vintage-season.