also: れいしゅ
noun
Sake served chilled, without heating. The reading ひやざけ is everyday; れいしゅ is more formal or used in writing/menus.
夏は冷酒がおいしい。
Cold sake is delicious in summer.
メニューには「冷酒」と書いてあった。
The menu said 'cold sake (reishu).'
Explicit spelling that includes the okurigana や, making the reading ひやざけ unambiguous.
Compound of 冷 (cold) and 酒 (sake). The reading ひやざけ is a native Japanese reading, while れいしゅ is the Sino-Japanese reading.