From Longman Dictionary of Contemporary Englishone by oneone by oneORDER/SEQUENCEused when one person or thing in a group does something, then the next, then the next, especially in a regular way One by one each soldier approached the coffin and gave a final salute. → one
Examples from the Corpus
one by one• One by one, worshipers walked to the front of the church.• At once Lord Boddy did the same, and one by one, as they listened and nodded, everyone else followed suit.• He examined them one by one.• Little puffs of dust rose up as he opened them, one by one.• Paul, Minnesota, and one by one three of the younger brothers who also became lawyers joined George there.• She ticks them off, one by one, on her long slender fingers.• The problems were then studied one by one in order of urgency.• They were all taken away by the Red Guards, broken one by one in the street.• We hold one another, then we return, one by one, each person saying a private good-bye. 