From Wiktionary, the free dictionary
summer-tower (plural summer-towers)
- movable tower used in sieges
- 1408, tr. Vegetius, De Re Militari (Douce) f. 110
- Scales, ladderes, & somertoures [L. ad capiendos muros scalae vel machinae] and alle suche gynnes..ben Iordeyned to clymbe vp walles & toures.
