old magazines; back issues of magazines
Refers to magazines that are old, used, or from past issues. Often used when talking about secondhand shops, recycling, or collections.
古雑誌を古本屋に売った。
I sold old magazines to a used bookstore.
この店にはたくさんの古雑誌が置いてある。
This shop has a lot of old magazines.
バックナンバー is a loanword for back issues of a periodical, often used in a more formal or commercial context. 古雑誌 is a broader, everyday term for old magazines.
Compound of 古 (ふる, 'old') and 雑誌 (ざっし, 'magazine'). The reading ふるざっし is a straightforward combination.