A / arrectārĭus
adjective

arrectārĭus

fem. arrectāria · neut. arrectārium
(), , arrectus
in an erect position; erect; perpendicular;
in an erect position, erect, perpendicular; hence, arrectaria, the upright posts of a wall (opp. transversarii, cross-beams), only Vitr. 2, 8, and 7, 3.