Sony SLR Terms

Designations for Sony Alpha SLR

DT - "Digital Technology", lenses for APS-C size sensors
G - G Series, professional lenses
SSM - "SuperSonic Motor", in-lens ultrasonic motor used on some long telephoto G Series

lenses.
ZA -"Zeiss Alpha", new lenses manufactured under license from Carl Zeiss

in case of anyone of you guys dont know what is APS-C size sensor here is the terms;

Advanced Photo System type-C (APS-C) is an image sensor format approximately equivalent in size to the Advanced Photo System "classic" size negatives. These negatives were 25.1 × 16.7 mm and had an aspect ratio 3:2. while the designations by brand include:
Canon - EF-S
Nikon - DX format
Pentax - DA
Sony - DT
Sigma - DC
Tamron - Di II
Tokina - DX