noun
Refers to a single step or stride in walking. Often used in set phrases like 歩を進める (take a step forward) or 歩を緩める (slow one's pace).
彼は一歩も動かなかった。
He didn't move a single step.
歩を速めて駅へ向かった。
I quickened my pace and headed to the station.
counter
counter for steps
Used to count steps or strides. Commonly appears with numbers, e.g., 一歩 (one step), 二歩 (two steps).
毎日一万歩を目標に歩いている。
I aim to walk 10,000 steps every day.
あと三歩でゴールだ。
Just three more steps to the goal.
足 refers to the foot or leg, while 歩 specifically means a step or stride.
歩く is the verb 'to walk', whereas 歩 is the noun for a step or the counter for steps.
The kanji 歩 depicts a foot and originally meant 'to walk'. The reading ほ is the Sino-Japanese on'yomi, used in many compounds related to walking or steps.