The word "ICU" stands for Intensive Care Unit. It is a special area in a hospital where patients receive very close medical attention and care. This unit is designed for people who are very sick or have serious injuries and need constant monitoring and support from doctors and nurses.
In medical contexts, you might hear more specific terms related to the ICU, such as "cardiac ICU" (for heart patients) or "neonatal ICU" (for newborns needing special care).
While "ICU" primarily refers to a hospital unit, in some contexts, people might use it informally to suggest someone is in a critical situation, but this is less common.
The ICU is a crucial part of a hospital where patients who are very ill receive specialized care.