A sumo wrestling ring (a circular earthen platform).
力士が土俵に上がると、会場は一層緊張感を帯びる。
When a rikishi steps into the dohyo, the venue takes on a heightened tension.
最後は土俵際の攻防で勝負が決まった。
In the end, the match was decided by a battle at the edge of the ring.
伝統行事では土俵入りの儀式が行われる。
At traditional events, the dohyo-iri (ring-entering ceremony) is performed.
Figuratively, a forum or arena for discussion/competition (e.g. 'the field of X').
教育の土俵で政策議論が繰り広げられた。
Policy debates unfolded in the arena of education.
国際ビジネスの土俵では小さな企業も工夫が必要だ。
In the arena of international business, even small companies need to be creative.
新しい技術が登場し、技術開発の土俵が変わった。
With new technologies appearing, the arena for technological development has changed.
A sandbag or gabion-like structure (used for earthworks or embankments) — a specialized/older usage.
洪水対策で土俵を積んで堤防を補強した。
For flood control, sandbag-like structures were stacked to reinforce the embankment.