duration vs length

duration and length both are nouns.

Word	Noun	Adjective	Verb	Adverb
duration	Yes	No	No	No
length	Yes	No	No	No

As nouns, duration and length are synonyms defined as:

duration (noun)	length (noun)
continuance in time	a section of something that is long and narrow
the property of enduring or continuing in time	the linear extent in space from one end to the other; the longest dimension of something that is fixed in place
the period of time during which something continues	continuance in time
	the property of being the extent of something from beginning to end
	size of the gap between two places