A signet is a ring bearing a seal used to stamp letters. A signet ring, press the signet into the wax, his father's signet.
The design is cut in reverse so the impression comes out the right way round, and possession of the ring once meant authority to act for its owner, which is why they were destroyed at a monarch's death. Modern signet rings are jewellery and seal nothing.
1nounsignetA ring bearing a seal used to stamp letters.
“He pressed his signet into the hot wax to seal the letter.”
signet is a ring.
Old French signet is a diminutive of Latin signum, a sign or mark.
Proto-Indo-European
*sekʷ-
Latin
signum — sign
Old French
signet — small seal
English, today
signet
From Old French signet (“small seal”), from Medieval Latin - signētum, diminutive of Latin signum (“sign”).
Etymology from Wiktionary, CC BY-SA