Definitions of Tyndall:

• noun:   British physicist (born in Ireland) remembered for his experiments on the transparency of gases and the absorption of radiant heat by gases and the transmission of sound through the atmosphere; he was the first person to explain why the daylight sky is blue (1820-1893)
• name:  A surname (rare: 1 in 50000 families; popularity rank in the U.S.: #6334)