This is the 2632nd most frequent Russian word.
укрепление
"Fortification" or "strengthening."
Here 'укрепление' refers to the action or process of strengthening one's health.
Укрепление здоровья важно для долгой жизни.
Strengthening health is important for a long life.
In this case, 'укрепление' denotes the technical process of making a structure more robust or stable.
Строители начали укрепление фундамента здания.
The builders began the strengthening of the building's foundation.
Here, 'укрепление' is used metaphorically to describe the development of better or stronger relationships between groups or countries.