Happōshu: a category of beer-like alcoholic beverages (low-malt beers) that are taxed differently from regular beer.
最近は発泡酒や第三のビールも種類が増えた。
Recently there are more varieties of happōshu and third-category beers.
安い発泡酒をまとめ買いした。
I bought a bulk pack of inexpensive happōshu.
この銘柄の発泡酒は泡立ちが良い。
This brand of happōshu has good foam.
Can also refer more generally to sparkling alcoholic drinks (e.g., sparkling wine), though in everyday use it usually means low-malt beer.
祝杯に発泡酒（スパークリングワイン）を開けた。
We opened a sparkling wine (sparkling alcoholic beverage) for the toast.
軽い発泡酒が食事に合う。
A light sparkling drink goes well with the meal.