noun
reusable cup; personal cup
Wasei-eigo from English 'my cup'. Refers to a personal, reusable cup brought by an individual, often for environmental reasons or at events.
wasei-eigo (Japanese-coined English), from my cup
カフェにマイカップを持っていくと割引になる。
If you bring your own cup to the café, you get a discount.
最近、マイカップ派が増えている。
Recently, the number of people who use their own cups has been increasing.