[tes.ter] n [ME, fr. MF testiere headpiece, head covering, fr. teste head, fr. LL testa skull, fr. L, shell] (14c): the canopy over a bed, pulpit, or altar
[2]tes.ter n [modif. of MF testart, fr. teston] (1546): teston a [3]test.er n (1661): one that tests or is used for testing