This question already has an answer here:

How many days in a week? Seven both to hear and speak. How many weeks in a month? Four, as the swift moon runneth.

What is the meaning of 'as the swift moon runneth'?

marked as duplicate by Jon Hanna, RegDwigнt Feb 7 '14 at 9:55

This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.


"Runneth" equals to "runs" in Modern English (see detailed answer). The writer compares the duration of the calendrical month to the duration of the Moon cycle, which are sort of close (quote from Wikipedia):

The average calendrical month, which is 1⁄12 of a year, is about 30.44 days, while the Moon's phase (synodic) cycle repeats on average every 29.53 days.


Leaving aside the archaic use of 'runneth' for 'runs', we have here a 'running' metaphor. The Sun is often said to 'run its daily course' especially by poets. This sounds far more interesting to most people than the utilitarian 'the Earth and the Sun revolve at what may be considered a fixed rate about the centre of mass of the two-body system'.

There are different definitions of 'month'. Calendar months are arbitrarily defined and variable. Lunar months are approximately equal to the four weeks of another definition, and far more nearly constant. However, even the term lunar month has been ascribed to different phenomenon-related intervals, of from about 27.3 to about 29.5 days. 28 days is some sort of average.


runneth is the third person singular of run. so here 'the swift moon runneth' means 'the swift moon runs'

Not the answer you're looking for? Browse other questions tagged or ask your own question.