Due to its reddish color, a totally eclipsed Moon is sometimes referred to as a "blood moon". In addition, in the 2010s the media started to associate the term "blood moon" with the four full moons of a lunar tetrad, especially the 2014–2016 tetrad coinciding with the feasts of Passover and Tabernacles. A lunar tetrad is a consecutive sequence of four lunar eclipses, spaced six months apart. The most recent blood moon occurred on October 8, 2014 and was visible across much of the Americas and Asia.
The Blood Moon Prophecy is a theory studied and taught by some Christian ministers, such as John Hagee and Mark Biltz, which states that an ongoing tetrad (a series of four consecutive lunar eclipses—coinciding on Jewish Holidays—with six full moons in between, and no intervening partial lunar eclipses) which began with the April 2014 lunar eclipse is a sign of the end times as described in the Bible in Acts 2:20 and Revelation 6:12.