سر (sar) is the Persian word for "head." It refers to the uppermost part of the human body, which houses the brain, eyes, ears, nose, and mouth. The head plays a crucial role in sensory perception and communication, making it essential for daily activities and interactions. In many cultures, the head is also symbolically significant. For instance, in Islam, it is common to show respect by lowering the head during prayer. Additionally, various traditions and rituals may involve the head, such as hair cutting or head coverings, which can signify different cultural or religious meanings.