Draconic Period of Revolution

the time interval between two successive passages of a planet (during its motion around the sun) or the moon (during its revolution around the earth) through the same orbital node (ascending or descending). The term “draconic” is connected with an idea of the ancients, according to which the sun and moon are devoured by a dragon during an eclipse. The moon’s draconic period of revolution (the so-called draconic month) has important significance in the theory of solar and lunar eclipses.