Cloud-to-Ground Lightning - Negative
A lightning discharge between cloud and ground initiated by a downward-moving, negatively-charged stepped leader. Abbreviated "-CG". Negative CGs are more common than positive CGs. Most of the lightning you can see striking the ground in a storm is of the negative cloud-to-ground variety. Negative cloud-to-ground lightning strikes can be identified visually and in photographs by their distinctive downward branching (aside from the portion of the channel very close to the ground, where upward leaders can be branched upward).
Negative CGs commonly consist of multiple "return strokes", which are additional pulses of current that illuminate the channel again and again. The first return stroke of a negative CG is usually the only branched one - the branches usually do not illuminate again in subsequent return strokes.