Abbreviation: PZD = "Piezo Drive" (Tamron)
The abbreviation PZD means "Piezo Drive" and is seen on Tamron products.
Explanation from Tamron
Piezoelectric drive replaces traveling wave energy with more efficient standing wave energy for higher AF performance with less weight and bulk. A vital contributor to compactness, PZD focuses quickly and precisely, assuring sharper results in demanding conditions with speed that captures spontaneous moments crisply—moments that might otherwise be lost to image softness. PZD is exceptionally quiet, making it ideal for nature, live performance shooting, golf and other conditions that demand quiet operation.