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ground; crust (earth); bed (gravel, river, etc.)
foundation (building, etc.); base
constituency; power base; support (electoral); footing; foothold
この地域は地盤が弱いそうなので注意だ。
I hear the ground is weak in this area.
政治家は地盤を固めることが大切だ。
It's important for politicians to solidify their base.
地盤沈下で道路にひびが入った。
Cracks appeared in the road due to ground subsidence.