Size chart
A table with the body measurements of each size in a size range and the increments between one size and the next.
It is the reference used to grade a base pattern. Each brand or manufacturer can define its own chart for its audience, which is why a size M can differ from one brand to another.
Example
If size M has a 96 cm bust circumference and size L has 100 cm, the increment for that measurement is 4 cm.