楷 means 'model / standard'. The script emerged in the late Han (2nd–3rd c.) and was perfected in the Wei-Jin and Tang periods (
钟繇,
王羲之,
欧阳询,
颜真卿,
柳公权 are the canonical masters). As a digital font,
楷体 renders characters in this brush-written model style — each stroke distinct, stable, upright — which is why it's the default font for children's learning materials.
