very small pictures or images, often used to preview larger versions; also the nails on people's thumbs.
Compound of 'thumb' (Old English 'thuma') and 'nail' (Old English 'nægel'). The term 'thumbnail' for a small preview image is relatively modern, emerging with digital technology.
When web designers created tiny preview images, they borrowed the word 'thumbnail' from actual fingernails—now the digital meaning is so common that kids use it without knowing what thumbs have to do with it.
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