ВО ФРОНТ (ФРУНТ obs) вытянуться, стать, стоять и т. п.PrepPthese forms onlyadv
(to come) to or (to be) in a position with one's arms at one's sides and one's heels together: (come) to attention
(stand) at attention.
Подходя к комендантскому дому, мы увидели на площадке человек двадцать стареньких инвалидов с длинными косами и в треугольных шляпах. Они выстроены были во фрунт (Пушкин 2). As we approached the commandant's house, we saw in a small square some twenty doddering veterans wearing three-cornered hats over their long hair. They were lined up, standing at attention (2a).