Kanji
A writing system imported from China several centuries ago and still in use today in Japan. Unlike katakana and hiragana, each pictogram does not represent a syllable, but meaning. Two or more kanji can be placed together to form compound words. You can also combine with hiragana.

Books aimed at a younger audience will often have furigana giving the pronunciation for kanji and its compounds.
"I don't know how to pronounce this word because it's written in kanji!"