hallmark的意思是特征;特点;金银纯度印记(打在金、银、铂制品上，表示纯度、生产日期及产地);给…打金银纯度印记。
牛津词典：
noun
1、特征；特点。
a feature or quality that is typical of sb/sth.
Police said the explosion bore all the hallmarks of a terrorist attack.
警方称这次爆炸具有恐怖分子袭击的所有特征。
2、金银纯度印记（打在金、银、铂制品上，表示纯度、生产日期及产地）。
a mark put on gold, silver and platinum objects that shows the quality of the metal and gives information about when and where the object was made.
verb
[VN]?给…打金银纯度印记。
to put a hallmark on metal goods.
柯林斯词典：
hallmark
1、N-COUNT?标志;特征;特点。
The?hallmark?of something or someone is their most typical quality or feature.
It's a technique that has become the hallmark of Amber Films...
这已经成为安伯电影公司的标志性技术。
2、N-COUNT?（金、银、铂制品上标明纯度、产地、制造者的）印记。
A?hallmark?is an official mark put on things made of gold, silver, or platinum that indicates the quality of the metal, where the object was made, and who made it.