1) A canopy over a bed, either suspended from the ceiling or supported on the posts.
1377 unum lectum integrum cum testers, howcez, tapetis, Bewick
1470 a white hangyng for a bedde, that is to saye a celour and testour with curteyns, Doncaster
1490 De j lez teister cum imagine B. M. vjd, York
1542 a ... teister of white and tawney saten embrothered, Bretton Hall
1695 the roofe ... redy to fall downe upon them when it raines they are forsed to get any thing they have upon the bed teasters to keep the water forth of the beed, Wetherby.