Readings that came from Chinese, written in katakana. Mostly used when the kanji is part of a compound word.
シュウ
Kun'yomi (訓読み)
Native Japanese readings, written in hiragana. Mostly used when the kanji stands alone. A dot marks where the kanji ends and the kana that follow it begin (as in いと.しい, 愛しい); a dash marks where other characters attach.