From Longman Dictionary of Contemporary Englishfirst come, first servedfirst served first comefirst come, first servedused to say that something will be given to the people who ask for it first, when there is not enough for everyone Tickets will be allocated on a first come, first served basis. → first
Examples from the Corpus
on a first come, first served basis• Seating is available on a first come, first served basis. 