1. a short description of something, giving only the main details
   • ● The first chapter provides a thumbnail sketch of the social and political climate of the US in the 1960s.

[TahlilGaran] English Dictionary ▲

a short or small picture or description
The new book included a thumbnail sketch of the author.

The police produced a thumbnail sketch of the bank robber.

[TahlilGaran] English Idioms Dictionary ▲