Webster's Revised Unabridged Dictionary · 1913

Lettic

Lettic (let"tik) , adjective

(a)
Of or pertaining to the Letts; Lettish.
(b)
Of or pertaining to a branch of the Slavic family, subdivided into Lettish, Lithuanian, and Old Prussian.
(a)
The language of the Letts; Lettish.
(b)
The language of the Lettic race, including Lettish, Lithuanian, and Old Prussian.