spacing vs placement

spacing and placement both are nouns.

Word	Noun	Adjective	Verb	Adverb
spacing	Yes	No	No	No
placement	Yes	No	No	No

As nouns, placement is a hypernym of spacing; that is, placement is a word with a broader meaning than spacing:

spacing: the property possessed by an array of things that have space between them
placement: the spatial property of the way in which something is placed

Other hypernyms of spacing include arrangement.

spacing (noun)	placement (noun)
the property possessed by an array of things that have space between them	the act of putting something in a certain place
the time between occurrences of a repeating event	contact established between applicants and prospective employees
	the spatial property of the way in which something is placed