Shigeru is a unisex Japanese given name derived from two kanji characters, "shigi" (四時) meaning "four seasons", and "ru" (る), which is a sound that does not have an independent meaning as a kanji character but serves as a particle in the given name. It can be written using various combinations of kanji characters with similar meanings, such as "四季る", "四時にる", or "四時流る".
The name Shigeru experienced a significant increase in popularity from 1915 onwards, peaking at 42 births in 1921. However, there was a steady decline thereafter, with the number of annual births falling to single digits by 1937.