Lewis & Short

ballistārĭus (balist-; and in Gloss. ballistrārĭus), ii, m. [1. ballista].

    1. A. A maker of ballistœ, Dig. 50, 6, 6: COLLEGIVM BALLISTARIORVM., Inscr. Orell. 4066.
    2. B. One who discharges the ballista, a slinger, Veg. Mil. 2, 2; Amm. 16, 2, 5.