From Longman Dictionary of Contemporary Englishthumbnailthumb‧nail1 /ˈθʌmneɪl/ adjective →thumbnail sketch/portraitRelated topics: Human, Computersthumbnailthumbnail2 noun [countable]1HBHthe nail on your thumb2a small picture of a document on a computer screen, showing you what it will look like when you print itClick on the thumbnails to view a larger version of each image.Examples from the Corpusthumbnail• Nestling between the two spools was a tinyplasticpacket, smaller than a thumbnail.• The Blackfeet let each thumbnail grow long, until it crooked like a claw.• Almost immediately her thumbnail found another grooveopposite; she pulled, and the star came out about a centimetre.• He'd given up woodwork, having driven a splinter through his thumbnail.• He opened a book with his thumbnail, as if afraid of dirtying his fingers.• He displayed a swollen, bruiseddigit and a mangledthumbnail.• It takes more than 400 pages of the manual to show thumbnails of them all.