2 sentences for 子 (zǐ — earthly branch)

1. 子时是指深夜十一点到凌晨一点。

   zǐ shí shì zhǐ shēn​yè shí​yī​diǎn dào líng​chén yī​diǎn.

   'Zishi' refers to the period from 11 PM to 1 AM.

   Source: Dong Chinese Dictionary

2. 指南针的刻度上，子代表北，午代表南。

   zhǐ​nán​zhēn de kè​dù shàng, zǐ dài​biǎo běi, wǔ dài​biǎo nán.

   On a compass scale, 'Zi' represents North and 'Wu' represents South.

   Source: Dong Chinese Dictionary