Jewelry refers to an adornment (generally precious metal or stone) worn by a person, like a bracelet, ring, necklace, or earrings. Jewelry may be purely decorative, or it may express something — like a ring that says you are married.
Humans have been in the jewelry business for a long time: A shell bracelet, or necklace was found in a cave in South Africa that dates back 75,000 years. Both a diamond ring from Tiffany’s and a handmade beaded bracelet are jewelry, but whether the jewel in jewelry is real or imitation, it is always spelled out. More than one piece of jewelry is still the same word.