Abbreviation: HID = "High Index / High Dispersion Glass" (Tamron)
The abbreviations means "High Index / High Dispersion Glass"
Explanation from Tamron
High Index, High Dispersion (HID) Glass for Better Color Correction
The use of HID (High Index, High Dispersion) glass elements in a lens can also be used to minimize on-axis and lateral chromatic aberrations that are the greatest hindrances to achieving high image quality. HID glass is another tool in the lens designer’s arsenal that has allowed Tamron to design and produce complex lenses such as long-range zooms that are conveniently compact and lightweight, and deliver outstanding performance.