ˌbaləˈstra(a)rēə noun
( plural balistrari·ae -rēˌē)
Etymology: New Latin, from Late Latin, feminine of balistrarius, ballistrarius of slinging, from Latin balista, ballista sling — more at ballista
: a narrow often cruciform opening in a wall (as a tower or fortress) for discharging arrows (as from a crossbow)