Ideographic Iteration Mark

It repeats the preceding kanji within the same word.

In 人々, the full spelling is 人人 and the word means “people”; in 時々, the character 時 repeats in a word meaning “sometimes.” The mark has no reading of its own: the complete word determines how it is read.

Marks for repetition long predate this character: examples are attested in China in the Shang era, an early dynasty, and in Japan before the Nara period, an early Japanese era. They let writers avoid writing repeated material in full.

Why can't 々 replace any repeated kanji?

Use it only when the same kanji repeats inside one word.

Write 民主主義, not 民主々義: the two 主 characters sit across a word boundary, between 民主 (“democracy”) and 主義 (“principle”). So 々 would join separate parts instead of shortening a repeated character in one word. Use it in established repeated forms.

How do you type 々?

Enter a Japanese conversion keyword, then choose 々.

A Japanese IME (input method editor) can offer the mark when you type onaji (おなじ), dou (どう), noma (のま), or odoriji (おどりじ). Select 々 from the candidates; available words vary by input system.