hornbook

n. 角贴书, 入门书

horn.book

n.（名词）
An early primer consisting of a single page protected by a transparent sheet of horn, formerly used in teaching children to read.
角帖书：一种早期初级读物，即为一张盖有透明角片作为保护的书页，以前供儿童认字用
A text that instructs in the basic skills or rudiments of a subject.
初级读物：教授某一学科的基本技巧或知识的读物