plēgē

At its root this word means a striking. It comes from the verb for hitting or beating, and it holds together both sides of that action: the blow that lands and the mark it leaves. In one setting it is the beating itself, the lashes and rods that fall on a person's back. In another it is the injury that remains afterward, the gash or scar a violent stroke leaves behind.

The New Testament uses it plainly of physical violence: prisoners flogged, an apostle beaten again and again, a traveler left half dead by robbers, and even the healed death-wound of the beast in Revelation. English needs different words for these shades, beating, blows, stripes, or wound, but each instance is easy to render, and a reader following a good translation will not be misled.

The same picture of a striking blow is lifted from the body to the world. When God strikes, the blow is a plague: a sweeping disaster that falls on people, cities, or the earth as an act of judgment. This is the sense that dominates Revelation, where the word appears far more than anywhere else.

Revelation reaches back to the plagues of Egypt for its imagery, so these blows arrive as hail, sores, scorching heat, and ruin, not only as disease. The word keeps its edge of a deliberate stroke: someone is being struck, and the striker is God. Calling these events plagues can make an English reader think first of an epidemic, but the underlying idea is broader, any devastating blow from heaven.