Adverb
one piece at a time
apart from others
in succession
Source: WordNetMen, it has been well said, think in herds; it will be seen that they go mad in herds, while they only recover their senses slowly, and one by one. Charles Mackay
I had assumed that I would age with all my friends growing old around me, dying off very gradually one by one. And here was a plague that cut them off so early. Thom Gunn
If one by one we counted people out For the least sin, it wouldn't take us long To get so we had no one left to live with. For to be social is to be forgiving. Robert Frost
To remove the hairs from a horse's tail, one by one must be plucked out. Latin Proverb
One by one we count the beans. Turkish Proverb
Grapes are eaten one by one. Egyptian Proverb