Thyra is from the Old Norse Þýri — possibly meaning "helpful" or "useful," related to the god Thor. Thyra Dannebod (c. 870-c. 935) — Queen of Denmark and wife of King Gorm the Old; mother of King Harald Bluetooth (after whom the wireless Bluetooth technology was named); one of the queens of medieval Denmark; the Jelling Stones (rune stones erected by Harald Bluetooth) — UNESCO World Heritage Site — commemorate her; she is credited in oral tradition with completing the Danevirke defensive wall against German invasions; one of the most-iconic figures in early Danish history. Thyra Boldsen — Danish sculptor. Thyra Heder — modern American author and illustrator.
Thyra does not currently appear in the US Social Security Administration's top 1,000 girls' names, so we don't publish a US rank or birth count for it. That says nothing about the name's standing elsewhere in the world — only that it sits outside the ranked US data we rely on.
In Pythagorean numerology the letters of Thyra reduce to 9, The Giver. This is a traditional interpretive system, not a factual claim about the name.