Small Arctic rodents, or used metaphorically to describe people who follow others mindlessly without questioning, like lemmings going over a cliff.
From Norwegian 'lemming,' possibly from Old Norse 'lemja' meaning 'to break.' The lemming became a metaphor for blind conformity because of a false myth about mass suicide.
The lemming myth—that they commit mass suicide by jumping off cliffs—is completely false, but it became so culturally powerful that we use 'lemmings' as a metaphor for mindless followers, showing how a lie can become language.
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