a step forward; one step forward
Used both literally and figuratively for progress or advancement, often in the context of gradual improvement or moving closer to a goal.
This agreement is a step forward toward peace.
He took a step forward and offered a handshake.
前進 means 'advance' or 'moving forward' in general, while 一歩前進 emphasizes a single, incremental step.
一歩 is 'one step' and can be used in many contexts; 一歩前進 specifically frames that step as progress.
Compound of 一歩 (ippo, 'one step') and 前進 (zenshin, 'advance'). The meaning is transparent from its parts.