thumbprint
/ˈθʌmprɪnt/noun
1- an impression or mark made on a surface by the inner part of the top joint of the thumb, especially as used for identifying individuals from the unique pattern of whorls and lines拇指印。
1.1
- figurative a distinctive identifying characteristic〈喻〉印记; 个性特征：
it has an individuality and thumbprint of its own.
它具有个性和自身的特征。