Veneer grades
Grades A and B are visually similar. They are sanded, and only tight knots and repairs are allowed.
Grades C and D are visually similar. They are unsanded, and knots and knotholes are allowed.
Grades A and C are structurally similar. Grade A is a patched grade C. Grade C has smaller defects/unbroken wood fibers than grade D and is therefore stronger.
Grades B and D are structurally similar. Grade B is a patched grade D.
from Sanded Plywood - APA (table 2)
from Grades and Specifications - APA (table 2)
