Being 'in the black' — financial surplus when income exceeds expenditures; profitability.
今年は売上が伸びて会社が黒字になった。
Sales increased this year and the company turned a profit.
家計を黒字にするために出費を見直した。
I reviewed expenses to make the household budget run in the black.
その事業部はここ数年ずっと黒字だ。
That division has been in the black for several years.
Black letter — text printed in black (as opposed to red or colored text), e.g., standard printed text.
契約書の条項はすべて黒字で印刷されている。
All clauses in the contract are printed in black letters.