doldrums /(dŏl"drŭmz)/

dol·drums

doldrums

n. pl.
  1. A part of the ocean near the equator, abounding in calms, squalls, and light, baffling winds, which sometimes prevent all progress for weeks; -- so called by sailors.

Phrases & Compounds
To be in the doldrums
to be in a state of listlessness ennui, or tedium.