From Longman Dictionary of Contemporary Englishfunction as something phrasal verbWORKING/NOT BROKENif something functions as a particular thing, it does what that type of thing normally does, or is used as that thing A library is functioning as a temporary hospital to cope with casualties. → function→ See Verb table
Examples from the Corpus
function as • These data strongly indicated that both N-terminal 73-205 and C-terminal 356-517 regions are essential for RAP74 to function as a transcription factor.• The same electronic system that provides flexibility to care for children or elderly parents at home can function as an electronic leash.• In this way, drawing can function as an interested adult, eliciting more language and more detail from the child.• Its function as banker to the government and to the monetary sector.• How, then, should a court confronted with the issue go about classifying a function as public or not?• These rhythm pipes and rhythm sticks are usually hollowed out and function as resonators.• The old structures are not only inadequate to meet our communications needs; they can not function as they once did.• Established by the National Security Council, the NSCIDs function as top secret bylaws for the intelligence community.From Longman Business Dictionaryfunction as something phrasal verb [transitive] to become something else or to do the work of another person or thingThe British Chamber of Commerce cannot function as a holding company, but can carry out service activities for the group.It took a year to train a group of people to function as general managers. → function→ See Verb table 