formulation vs expression

formulation and expression both are nouns.

Word	Noun	Adjective	Verb	Adverb
formulation	Yes	No	No	No
expression	Yes	No	No	No

As nouns, formulation and expression are synonyms defined as:

formulation (noun)	expression (noun)
inventing or contriving an idea or explanation and formulating it mentally	the act of forcing something out by squeezing or pressing
the style of expressing yourself	the feelings expressed on a person's face
a substance prepared according to a formula	a word or phrase that particular people use in particular situations
	the style of expressing yourself
	expression without words
	a group of symbols that make a mathematical statement
	the communication (in speech or writing) of your beliefs or opinions
	a group of words that form a constituent of a sentence and are considered as a single unit
	(genetics) the process of expressing a gene