Blazon, Strictly taken, signified, the Explication of Arms, in apt and significant Terms; more largely, it is taken for a Display of the Vertues of the Bearers of Arms.

From The Grammar of Heraldry by Samuel Kent, p10

All the flourishing Kingdoms and States of the Old (or Poetick) World, that were any thing civiliz’d, had a different Portraict on their Shields, for Distinction.

From The Grammar of Heraldry by Samuel Kent, p ix