hallmark

Etymology

1721. hall + mark, from Goldsmiths' Hall in London, the site of the assay office, official stamp of purity in gold and silver articles. The general sense of "mark of quality" first recorded 1864. Use as a verb from 1773.

noun

1. A distinguishing characteristic.
   Arsene Wenger's side showed little of the style and fluidity that is their hallmark but this was about digging deep and getting the job done, qualities they demonstrated and that will serve them well as the season reaches its climax. February 1, 2011, Phil McNulty, “Arsenal 2 - 1 Everton”, in BBC
2. An official marking made by a trusted party, usually an assay office, on items made of precious metals.
   It can highlight our embodiment, a qualitative step away from the hallmark machines that work so resolutely to disembody us. 2007, John Zerzan John, Silence

verb

1. To provide or stamp with a hallmark.
   The cane was undoubtedly of foreign make, for it had a solid silver ferrule at one end, which was not English hall–marked. 1905, Baroness Emmuska Orczy, chapter 2, in The Ayrsham Mystery