Resolution in ultrasound describes the system’s ability to distinguish between structures. Axial resolution is the ability to differentiate two objects along the beam axis (line of sight) and is determined by pulse length — shorter pulses improve axial resolution. Lateral resolution is the ability to distinguish two objects side by side perpendicular to the beam and depends on beam width and focus. Temporal resolution refers to the frame rate — how quickly the image is updated — and is critical for imaging moving structures such as the heart.