1The number zero (0); represents the absence of quantity. Used constantly in everyday life and in math. The more formal word 零 (rei) means the same thing, but ゼロ is the common everyday term.
今朝の気温はゼロ度だった。
This morning's temperature was zero degrees.
試合は3対0でうちのチームが勝った。
Our team won the match three to zero.
電話番号は最初にゼロを付けてかけてください。
Please dial the phone number starting with a zero.
その商品はもう在庫がゼロになっている。
That item's stock has already dropped to zero.
2A colloquial, figurative use meaning "nothing at all" or "equal to nothing" — describing a state or degree rather than an actual count.
最近やる気がゼロで、何も手につかない。
Lately my motivation has been zero, and I can't get anything done.
料理の経験はほぼゼロだったので、失敗ばかりだった。
I had almost zero cooking experience, so I kept failing.