Abarim Publications' online Biblical Hebrew Dictionary
The Hebrew root בזק (bzq) is not used in the Bible, but it exists as verb in Aramaic where it means to scatter. Its derivation, the masculine noun בזק (bazaq) is used only once, in Ezekiel 1:14, where the four Cherubim zip to and fro like a bazaq.
Since just prior Ezekiel sees lightening flashing from the central fire (Ezekiel 1:13), it is assumed that bazaq probably means a bolt of lightening. But the emphasis should lie on its scattering nature.