Young domestic cats, typically from birth until about one year of age.
From Old French 'chaton' and Medieval Latin 'cattus,' with the diminutive suffix '-en' added to show smallness. The word entered English around the 14th century and has remained virtually unchanged because kittens stayed so appealing that nobody needed to rename them.
Kittens trigger something so powerful in the human brain that they've basically conquered the internet—cat videos are one of the most-watched things online. Evolution made them adorable on purpose (big eyes, playful behavior) to keep their mothers protective, and we're completely fooled by the same tricks that work on mother cats!
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