middle passage

noun2

1. •
   (historical) Specifically, the middle part of the sea voyage by which slaves were transported from Africa to America.

   • The city once laid claim to the largest fleet of slave ships in the history of the trade as its merchants overtook Bristol and London in dominating the Middle Passage. — 2007
2. •
   (no longer used) A middle way, especially between two extremes; an intermediate path in space or time.