Correct spelling, explanation: a well-known word running has a long history as it could already be found in Old English forms rinnan and irnan. The origin of the word running, however, is in the Germanic language, but it also existed in Old Norse. The form of running spelled with the –u letter, as we use it today, appeared in the 16th century.

Definition of running:
1. adjective – when something happens a few times in a row;
He’s won the race for the third time running.
2. noun – moving quickly using your feet;
I go running every day before breakfast for a better start to the day.
3. noun – controlling or taking care of something;
Running the company on your own is a difficult thing to do.

Collocations with running:
Some typical and common collocations include:
1. running water – freshwater we use every day;
We stayed in a budget hotel where there was no running water.
2. running shoes – shoes you use for running;
Once I come back from work I put on my running shoes and go jogging.
3. running machine – a type of machine that is used for running indoors;
During winter I prefer running with the use of a running machine.

Incorrect spelling, explanation: the base form of the word running is to run, which features a single -n letter. As a result, many users of English make a mistake and spell the word running with a single -n, too and that ends up with an incorrect form runing. We need to double the -n letter as there is one vowel before it.