天底

nadir

天的英语翻译：

day; God; Heaven; nature; sky; weather
【法】 sky

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