D defs.my
Entry 1 sense Webster, 1913

doldrums

/(dŏl"drŭmz)/ · dol·drums · IPA /ˈdɑldɹəmz/
01 n. pl. A part of the ocean near the equator, abounding in calms, squalls, and light, baffling winds, which sometimes prevent all progress for week…
  1. 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.