Both literal (a place to put one's foot when climbing) and figurative (a starting point or means to achieve something). Often used in phrases like 足掛かりを作る (gain a foothold) or 足掛かりとする (use as a stepping stone).
I had trouble climbing the cliff because there were no footholds.
この仕事を足掛かりにして、もっと大きなプロジェクトに挑戦したい。
I want to use this job as a stepping stone to take on bigger projects.
We created a foothold to expand into a new market.
I aim to use this experience as a stepping stone toward independence.
The company gained a foothold in the Asian market.
We ended up losing our foothold in the negotiations.