What does mean zhōngxing from ZTE in Chinese?
中兴通讯的前身是1985年由航天系统的691厂以及运兴香港电子等共同投资创办的“中兴半导体”。而“中兴”名字由来有二：一是因为691厂是中方企业，港资企业为运兴，各取一字，成为“中兴”；第二个更为重要的原因是“中兴”暗含中国兴旺的意思。这也正表达了当时创业者侯为贵寄望中兴通讯振兴民族通信产业的理想。后来，中兴通讯称谓先后经历了中兴维先通、中兴新的变化，但始终坚持“中兴”二字。如今，“中兴通讯，中国兴旺”已写入中兴通讯企业文化的第一条。


Source: ZTE official site

If you cannot read Chinese, you may refer to the following translations in my poor English:

There are two reasons why this company is called [中兴]:


ZTE is combined by two corporations: 中国航天691厂(CASC 691 Factory, a Chinese company) and 兴运 (Xing1 Yun4, a Hong Kong company). take one word from each company, we get[中] and [兴].
Like other users said, 中兴=中国兴盛=China's soaring.