Webster's Revised Unabridged Dictionary · 1913

Guitar

Guitar , noun

[French guitare; compare Pr., Sp., & Portuguese guitarra, Italian chitarra; all from Greek {not transcribed}; compare Latin cithara. Compare Cittern, Gittern.]

A stringed instrument of music resembling the lute or the violin, but larger, and having six strings, three of silk covered with silver wire, and three of catgut, -- played upon with the fingers.