one by one

Adverb

• apart from others
  • taken individually, the rooms were, in fact, square
    
  • the fine points are treated singly
    

• one piece at a time
  • she sold the plates by the piece
    

• in single file
  • the prisoners came out one by one
    

Related words

• Synonyms: 
  individually , separately , singly , severally , on an individual basis , by the piece , one after another , one at a time