| 1. | an official mark or stamp indicating a standard of purity, used in marking gold and silver articles assayed by the Goldsmiths' Company of London; plate mark. |
| 2. | any mark or special indication of genuineness, good quality, etc. |
| 3. | any distinguishing feature or characteristic: Accuracy is a hallmark of good scholarship. |
| 4. | to stamp or imprint (something) with a hallmark. |