How long is this period of time considered? Could affect the definition of "running" for other things.

Semantics.

You can run for two seconds and it's still running. You can watch a rain drop run from the top of your windshield all the way down.

Or you could view running in it's adjective form, which is designed to describe phenomena such as moving water.

never had a runny nose? ^^

My nose has never tried to run, no.

its figurative, words are very fluid.. you should take an intro course in linguistics, it might answer your question

Cause if you look at it river water under a microscope, you can see the particles running on their legs, making the river move. Hence running water. Lake water particles don't have the legs to move/run so it's not referred to as running water, but aka "still water"

This post was edited by Gekkostate on Jan 4 2012 07:33pm

Run (verb)
the modern verb is a merger of two related O.E. words. The first is rinnan, irnan (strong, intransitive, pt. ran, pp. runnen), from P.Gmc. *renwanan (cf. M.Du. runnen, O.S., O.H.G., Goth. rinnan, Ger. rinnen "to flow, run"), both from PIE *ri-ne-a-, nasalized form of base *reie- "to flow, run" (see Rhine)

Rhine
principal river in western Germany, from Ger. Rhein, from M.H.G. Rin, ult. from Gaulish Renos, lit. "that which flows," from PIE base *reie- "to move, flow, run" (cf. Skt. rinati "causes to flow," ritih "stream, course;" L. rivus "stream;" O.C.S. reka "river;" M.Ir. rian "river, way;" Goth. rinnan "run, flow," rinno "brook;" M.L.G. ride "brook;" O.E. riþ "stream;" O.E. rinnan, O.N. rinna "to run," Du. ril "running stream"). The spelling with -h- (cf. L. Rhenus; Fr. Rhin) is from infl. of Gk. form of the name, Rhenos.

http://www.etymonline.com/index.php?term=run&allowed_in_frame=0

Water that isn't moving is standing...maybe that has something to do with it

Just grammar is my guess

The Germans invented English to make people stupid and easier to control.
So it's our fault that things don't make sense. We're anti-intelligence.

English is the stupidest language.
Around the world people danced in circles until us yanks invented square dancing. We intentionally go against the grain.
People around the world use the metric system and know there's 1k meters in 1 kilometer but ask an american how many yards (the american meter) are in 1 mile (the american kilometer).
I haven't found a single one who can answer correctly off the top their head. Is it by design or is evolution going the wrong way? We're devolving.