'bit by bit' definitions:

Definition of 'bit by bit'

(from WordNet)
adverb
A little bit at a time; "the research structure has developed piecemeal" [syn: piecemeal, little by little, bit by bit, in stages]
adverb
In a gradual manner; "the snake moved gradually toward its victim" [syn: gradually, bit by bit, step by step]

Synonyms of 'bit by bit'

From: Moby Thesaurus