the.com/forklightning

means A lightning bolt that splits into multiple branches resembling the tines of a fork, forking across the sky in several jagged paths rather than striking as a single line.

from A transparent compound of "fork" and "lightning." "Fork" comes from Old English "forca," itself borrowed from Latin "furca," a pitchfork or pronged tool — the same root that gives us "bifurcate." The verb sense, "to split into branches," is what does the work here: lightning that divides like a fork's tines. "Lightning" is the older "lightening," from "light," the sky briefly made bright. So the word is just two plain English pieces describing exactly what the eye sees — branching fire.