safety factor vs factor of safety

safety factor and factor of safety both are nouns.

Word	Noun	Adjective	Verb	Adverb
safety factor	Yes	No	No	No
factor of safety	Yes	No	No	No

As nouns, safety factor and factor of safety are synonyms defined as:

safety factor and factor of safety: the ratio of the breaking stress of a structure to the estimated maximum stress in ordinary use

safety factor (noun)	factor of safety (noun)
the ratio of the breaking stress of a structure to the estimated maximum stress in ordinary use	the ratio of the breaking stress of a structure to the estimated maximum stress in ordinary use