宝 (Skt; Jpn hoor takara)
Jewel, gem, treasure, or anything precious. Ratna is a component of a number of Sanskrit Buddhist terms and names.
For example, Ratnaketu, or Jewel Sign, is the name that two thousand voice-hearers will bear when they become Buddhas,
according to the "Prophecies" (ninth) chapter of the Lotus Sutra.
Prabhutaratna is the name of the Buddha Many Treasures, who appears in the "Treasure Tower" (eleventh) chapter of the Lotus Sutra to lend credence to the sutra, which Shakyamuni Buddha is preaching.
The word prabhuta means abundant, numerous, etc. Sapta-ratna is the term for the seven kinds of treasures or gems often mentioned in the Buddhist scriptures.
Tri-ratna is the three treasures;
the Law (his teachings), and
the Buddhist Order (Ssangha)(community of believers).