Meaning

noun a state of inactivity (in business or art etc)

noun a belt of calms and light winds between the northern and southern trade winds of the Atlantic and Pacific

originFrom obsolete doldrum (“slothful or stupid person”) plus the plural suffix -s. Doldrum is possibly derived from dull or Middle English dold (past participle of dullen, dollen (“to make or become blunt or dull; to make or become dull-witted or stupid; to make or become inactive”), from dul, dol, dolle (“not sharp, blunt, dull; not quick-witted, stupid; lethargic, sluggish”); see further at dull),…

Etymology from Wiktionary, CC BY-SA 3.0