high board
/ˌhʌɪ ˈbɔːd/noun
1A raised table at which distinguished guests are seated at a feast, banquet, etc. Compare high table adjective. Now historical.
2 Sport. The higher or highest of two or more diving boards; specifically the 10m rigid board of a diving platform used in diving competitions; diving from this board as an event in a diving competition; platform diving.
adjective
Usually in form highboard. Of, relating to, or designating diving from a high diving board.
Origin
Middle English; earliest use found in Guy of Warwick. From high + board.