noun
Usage: usually capitalized B&A
: a screw thread with an angle of 47 1/2° and rounded crests and roots that is used chiefly in Great Britain and other European countries for very small screws
noun
Usage: usually capitalized B&A
: a screw thread with an angle of 47 1/2° and rounded crests and roots that is used chiefly in Great Britain and other European countries for very small screws
Webster's New International English Dictionary. Новый международный словарь английского языка Webster. 2012