The word "乾隆" is formed by combining the character "乾", denoting heaven or the celestial, with "隆", meaning prosperous or grand, to create a compound signifying "heavenly prosperity", which was selected as the era name for the Qing dynasty emperor Hongli.
Word Definition - 乾隆
qián lóngthe Qianlong era; Qianlong Emperor (1711–1799), sixth Qing emperor, princely title 寶親王|宝亲王[bǎo qīnwáng], personal name 弘曆|弘历[hónglì], reigned 1735–1799