Oxford University Press has named “brain rot” its word of the year. It's defined as “the supposed deterioration of a person’s mental or intellectual state,” especially from consuming too much low-grade online content.

The first recorded use of “brain rot,” according to Oxford University Press, was in Henry David Thoreau’s Walden, published in 1854. “While England endeavours to cure the potato-rot, will not any endeavour to cure the brain-rot, which prevails so much more widely and fatally?” wrote Thoreau in his treatise on transcendentalism.

Oxford University Press said the phrase "brain rot" gained "new prominence in 2024," with its frequency of use increasing 230% from the year before.