棱底向下

棱的英语翻译：

arris; edge; ridge

底的英语翻译：

a copy kept as a record; base; bottom; end; fundus; the truth of a matter
【医】 base; basement; bases; basi-; basio-; basis; batho-; bathy-; fimdi
floor; fundus; pavimentum; solum

向下的英语翻译：

down; alow; downhill; downward
【计】 down
【医】 cata-; deorsum; kat-