(also pluteum). The root meaning of 'enclosure, screen or shelter made of boards or latticework' extends to several objects:
[1] Breastwork
As a military t.t, a special breastwork or screen used by the testudo (Vitr. De arch. 10,15,1; cf. Siegecraft).
[2] Wooden fence
A wooden fence (Liv. 10,38,5) or even a small wooden temple (Anth. Lat. 139, 158).