The arrow in a crossbow is called a “bolt”.

A modern archer will tell you that the main difference between an arrow and a bolt is length. If it's less than 16 inches long, it's a bolt. If it's longer, it's an arrow, even if it's fired from a crossbow. A lot of people still call them bolts anyway. Crossbow bolts are often not fletched, but that's not a requirement.

The word bolt is very old, from Proto-Germanic *bultas possibly meaning arrow, missile, and further back from Proto-Indo-European *bheld- meaning to knock, strike. The idea of a bolt of lightning apparently comes from Middle English in the 16th century.

Meanwhile, lightning travels at the pretty much the speed of light.

The light from lightning travels at the speed of light, which is 670 million miles per hour. The actual lightning bolt travels at about 270 thousand miles per hour.

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SuStel
http://trimboli.name