One of the mysteries of the English language finally explained.
1Fire or flame in the shape of a ball; especially applied descriptively to luminous meteors and ball lightning. Also specifically: the fireball resulting from the explosion of a nuclear device.
2A person of great liveliness or spirit.
great balls of fire
Informal (originally and chiefly US) : used as an exclamation to express amazement or delighted surprise.
Late 16th century; earliest use found in Arthur Golding (d. 1606), translator. From ball + of + fire.
ball of fire/ˌbɔːl əv ˈfʌɪə/
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