Noun
quarter pipe (plural quarter pipes)
Alternative form of quarter-pipe
(skateboarding, snowboarding, skiing, BMX, rollerskating, etc.) A structure used to perform tricks, approximately half the size of a half-pipe, similar in appearance to having a quarter of a circle in cross-section, with the middle of that quarter as the bottom.
(skateboarding, snowboarding, skiing, BMX, rollerskating, etc) A ramp, one side of a halfpipe
Source: en.wiktionary.orgquarter-pipe