Mathematica Tutorial: Visualization And Graphics - Wolfram Research

Visualization and Graphics 49
Graphics directives which require a numerical size specification can also accept values of Tiny,
Small, Medium, and Large. For each directive, these values have been fine-tuned to produce an
appearance which will seem appropriate to the human eye.
In[12]:=
This specifies a large thickness with medium dashing.
Plot@Sin@xD, 8x, 0, 2 Pi