本义是“鸺”（猫头鹰类）。甲骨文的字形像一只有着圆睁的眼睛和翘起的头羽的凶鸟，正蹲踞在巢里。后来假借为新旧的“旧”，本义就不存在了。

This character’s original meaning was “鸺,” a kind of owl. On oracle bone inscriptions, it looked like a fierce bird perched in a nest, its eyes open wide and the feathers on its head raised. Later, the meaning changed to “old.”

1、Zhèxiē shì wǒ shōucáng de jiùshū.
这些是我收藏的旧书。

This is my collection of old books.

2、Tā yīnwèi jiùbìngfùfā bùnéng qù shàngbān le.
他因为旧病复发不能去上班了。

He can’t go to work because of a relapse in his illness.