In the Bible, "wormwood" is a term that appears in both the Old and New Testaments. In the Old Testament, the Hebrew word לענה (laanah) is translated into English as "wormwood" and occurs eight times, always with the implication of bitterness. In the New Testament, the Greek word apsinthos, which is rendered with the English "wormwood," is mentioned only once in the Book of Revelation).

In Revelation, "wormwood" is the name of a star that falls from the sky and makes a third of the waters of the earth bitter and undrinkable. This is the third of the "trumpet judgments" described in Revelation, and it is believed to be a symbolic representation of the bitterness that will fill the earth during troubled times).

The word "wormwood" was a well-known bitter herb in Bible times, so by naming the star Wormwood, it is suggested that its effect will be to embitter the waters of the earth so much that they become poisonous. If drinking water is unavailable to one third of the earths population, it is easy to see how chaos and terror will result.

While wormwood is certainly one of the more obscure words in the Bible, it has worked its way into modern usage in interesting ways. For example, it is the name of a certain notorious plant, and it was also made popular by C.S. Lewis in one of his books.