stratum vs stratify

stratum is a noun but stratify is not a noun.

Word	Noun	Adjective	Verb	Adverb
stratum	Yes	No	No	No
stratify	No	No	Yes	No

stratum (noun)	stratify (noun)
an abstract place usually conceived as having depth
a subpopulation divided into a stratified sampling
people having the same social, economic, or educational status
one of several parallel layers of material arranged one on top of another (such as a layer of tissue or cells in an organism or a layer of sedimentary rock)

stratum (verb)	stratify (verb)
	render fertile and preserve by placing between layers of earth or sand
	form layers or strata
	form, arrange, or deposit in layers
	divide society into social classes or castes
	develop different social levels, classes, or castes