That or who serves or serve.

(uncountable) The action of the verb to serve. / (countable) An amount of food or drink for or served to one person; especially in relation to a meal.

present participle of serve

plural of serving

to give or provide something to another person

plural of second serve

Third-person singular simple present indicative form of serve time

If I have correctly remembered the details.

Third-person singular simple present indicative form of serve one's time

Third-person singular simple present indicative form of serve someone right