The Sony FE/E mount replaced the Sony A mount (originally a Minolta film autofocus lens mount). The Sony FE/E mount is for the Sony mirrorless camera. Full frame lenses are referred to as FE mount. Cropped frame mirrorless lenses are referred to as E mount. Cropped frame cameras like the A6000 series can take both FE and E mount lenses. While full frame cameras like A7c, A7 and A9 series take both FE and E mount lenses, it is best to use the FE full frame lenses since the glass will cover the larger sensor. If you use an E mount lens on full frame camera, it will affect the focal length as well as drop the megapixel or file size of the image. Note A7 has full frame sensor while A6500 has cropped frame sensor.
G – stands for “Gold” and are considered Sony's best lenses.
ZA – Zeiss Alpha, Zeiss branded lenses designed specifically for Sony cameras. Zeiss makes great glass.
SSM – SuperSonic Motor, Very fast and quiet autofocus and usually are well sealed and durable.
SAM – Smooth Autofocus Motor is fast and quiet but are often of plastic build.
OSS – Optical SteadyShot means optical stabilization is housed in the lens. This can help you stabilize the lenses when hand holding.
PZ – stands for “Power Zoom” and specifies lenses that have inbuilt motors to operate the optical zoom. Most are small lenses used for video.
ED – Extra-low Dispersion glass elements in the lens that may reduce chromatic aberrations.