Dic: serve as something, serve to do something

• Her death should serve as a warning to other young people.
• A single example serves to illustrate what I mean.
• The judge said the punishment would serve as a warning to others.
• The attack was unsuccessful and served only to alert the enemy.

* * *

[HAVE AN EFFECT] [Intransitive] formal | to have a particular effect or result (serve as, serve to do sth) .

[HAVE PARTICULAR RESULT] ~ as sth | to have a particular effect or result.

.... LDOCE, OALD

• She ushered me into the front room, which served as her office.
• I really do not think that an inquiry would serve any useful purpose.
• Their brief visit has served to underline the deep differences between the two countries.
• The old drawing room serves her as both sitting room and study.

3 [VERB] V as/for n, V n, V to-inf, V n as/for n

If something serves as a particular thing or serves a particular purpose, it performs a particular function, which is often not its intended function.

.... Cobuild