This is the 3807th most frequent Russian word.
foundation
The Russian word "foundation" (фундамент) means the base or groundwork upon which something is built or established.
Here, 'фундамент' is used in a concrete sense, referring to the basic structure supporting a building.
Фундамент дома был построен из камня.
The foundation of the house was built from stone.
'Основу' here metaphorically describes the fundamental ideas or principles supporting the law.
Его предложения легли в основу нового закона.
His proposals formed the foundation of the new law.
'Основой' conveys the idea of fundamental actions or efforts that support future achievements.