Veneer specifications define the thin wood's species, cut (plain, quarter, rotary), grade (quality/defects), thickness (0.6-2.5mm), size, and backing, influencing its appearance (grain, color) and application, with key factors including wood species for color/grain, cut for pattern, matching for flow, and backing for stability (paper, phenolic, wood-on-wood), all crucial for achieving desired aesthetics and performance in architectural woodwork or furniture.