1) at bottom (formal) the way a person or situation really is, although they may seem different
ENGLISH:
She's a good kind person at bottom.
PORTUGUESE:
Ela é uma pessoa bondosso no fundo.
2) be at/hit/reach rock bottom to be in a very bad situation that could not be any worse
ENGLISH:
I was at rock bottom, and knew I had to try and stop drinking
PORTUGUESE:
Eu estava no fundo do poço e sabia que eu tinha que tentar parar de beber.
3) bottom DRAWER (BrE) all the things, especially things that you use in a house, that a woman collects to use when she's married = (AmE)
hope chest
ALSO: wedding chest (AmE), glory box (UK/AUS)
ENGLISH:
She's already started her "hope chest" for living on her own.PORTUGUESE:
Ela já começou seu "enxoval" para ir morar sozinha.ENGLISH:
... which she's saved in her hope chest ...PORTUGUESE:
... que ela guardou em seu enxoval ...ENGLISH:
She begins filling her hope chest as she initiates a campaign to win Silas's heart.PORTUGUESE:
Ela começa a juntar seu enxoval enquanto inicia uma campanha para conquistar o coração de Silas.ENGLISH:
... and later stockpiled her hope chest with china and pots and pans ...PORTUGUESE:
... e depois encheu seu enxoval com porcelana e panelas ...SOURCE: Longman Dictionary of Contemporary English + Google! :)