1.
buzzword, trendy word/expression, catchword
A word or phrase that becomes widely popular during a particular period, often reflecting social trends, current events, or popular culture. May fade from use over time.
Cultural note
Every year, the 新語・流行語大賞 (New Words and Buzzwords of the Year) awards are announced in Japan, selecting the most notable expressions from that year. Past winners reflect social phenomena, political events, sports achievements, and pop culture trends. The awards are closely followed by the media and are a reflection of that year's cultural landscape.