popular product; hot item; best-seller
Refers to a product that is currently in high demand or selling well. Often used in retail, marketing, and consumer contexts.
This popular product sold out immediately.
I check out the newly released hot items.
人気商品 is a broad term for any popular product, whereas 売れ筋 specifically highlights strong, ongoing sales performance in a retail/business sense.
Compound of 人気 (にんき, 'popularity') and 商品 (しょうひん, 'product').