CRC System
The Close-Range Correction (CRC) system is one of Nikon's most important focusing innovations, providing superior image quality at close focusing distances and increasing the focusing range. With the CRC system, lens elements are configured in a "floating element" design, where each lens group moves independently to achieve focus. This ensures superior lens performance even when shooting at close distances. The CRC system is used in fisheye, wide-angle, micro, and selected medium telephoto NIKKOR lenses.
M/A
Some NIKKOR lenses feature a focusing mode that allows switching from automatic to manual focus with virtually no delay, simply by rotating the focus ring on the lens. This makes it possible to smoothly transition to manual focus while looking through the viewfinder.
Silent Wave Motor
This technology converts "traveling waves" into rotational energy to focus the lenses. This allows for high-speed autofocus that is extremely accurate and super quiet.
SIC
This is Nikon's term for the multi-layer coating of optical elements in NIKKOR lenses.