expression vs formulation

expression and formulation both are nouns.

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

As nouns, expression and formulation are synonyms defined as:

expression (noun)	formulation (noun)
the act of forcing something out by squeezing or pressing	inventing or contriving an idea or explanation and formulating it mentally
the feelings expressed on a person's face	the style of expressing yourself
a word or phrase that particular people use in particular situations	a substance prepared according to a formula
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