a nominal last measurement, rather than a measurable dimension, calculated by adding an allowance for toe space to stick length of the foot
sometimes equal to the last size marked on a last
Common toe allowances in English and American sizing include 2 or 3 barleycorns.
Several approximations commonly used in patterning are based on multiples of nominal standard last length, such as for counter point height or heel length.
Every dealer who uses the size stick is familiar with the necessity of allowing two or more sizes above the actual measurement of the foot. On somewhat the same principle, anybody who takes a modern last and sets it in the size stick will find that it draws usually from a size to a size and a half above its marked measure.
— The Shoe and Leather Lexicon, Fourth Edition, 1918