tranche n., pl. tranches [Fr. slice, installment.] Portion or installment. Portion of bond issue for distribution in another country. The World Bank has released an initial tranche of 250 million dollars out of a total of 452 million to be granted to Nigeria… (Sunday Tribune 1986).
This is a word you might have heard in the news over the last couple of years.
From Word Dictionary of Foreign Expressions.