pier vs span

pier and span both are nouns.

Word	Noun	Adjective	Verb	Adverb
pier	Yes	No	No	No
span	Yes	No	Yes	No

pier (noun)	span (noun)
a platform built out from the shore into the water and supported by piles; provides access to ships and boats	the act of sitting or standing astride
a support for two adjacent bridge spans	a structure that allows people or vehicles to cross an obstacle such as a river or canal or railway etc.
(architecture) a vertical supporting structure (as a portion of wall between two doors or windows)	the distance or interval between two points
	a unit of length based on the width of the expanded human hand (usually taken as 9 inches)
	two items of the same kind
	the complete duration of something

pier (verb)	span (verb)
	to cover or extend over an area or time period