- Supermoon = is the coincidence of a full moon or a new moon with the closest approach the Moon makes to the Earth on its elliptical orbit, resulting in the largest apparent size of the lunar disk as seen from Earth. The technical name is the perigee-syzygy of the Earth-Moon-Sun system (Wikipedia).
- Blood-moon = when the Earth eclipses a full Moon, the direct sunlight is blocked, but the sun's rays still light up the moon. This light, however, has travelled through the Earth's atmosphere first, and sometimes causes the totally eclipsed Moon to look red or brownish (source: timeanddate.com).
- Harvest Moon = the full moon closest to the Autumnal Equinox.
- Lunar Tetrad = four successive total lunar eclipses, with no partial lunar eclipses in between, each of which is separated from the other by six lunar months (six full moons).
Joel 2:31 (see also Acts 2:14-21)The sun shall be turned to darkness, and the moon to blood, before the great and terrible day of the Lord comes.
Revelation of Saint John (The Apocalypse) 6:12-17When he (the Lamb) opened the sixth seal, I looked, and behold, there was a great earthquake; and the sun became black as sackcloth, the full moon became like blood, and the stars of the sky fell to the earth as the fig tree sheds its winter fruit when shaken by a gale; the sky vanished like a scroll that is rolled up, and every mountain and island was removed from its place. Then the kings of the earth and the great men and the generals and the rich and the strong, and every one, slave and free, hid in the caves and among the rocks of the mountains, calling to the mountains and rocks, “Fall on us and hide us from the face of him who is seated on the throne, and from the wrath of the Lamb; for the great day of their wrath has come, and who can stand before it?”