The number seven, used for counting objects with the native Japanese counter つ.
There are seven apples on the desk.
seven years old
Specifically refers to the age of seven, often in contexts like traditional celebrations (e.g., Shichi-Go-San).
My daughter will be seven this year.
four o'clock (old time system)
In the old Japanese temporal hour system, 七つ corresponded to the modern hour of around 4 a.m. or 4 p.m. Rare outside historical contexts.
In the Edo period, 'ake nanatsu' referred to around 4 a.m.
There are seven mandarin oranges on the desk.
My daughter will turn seven next month.
The bell rang at the old hour of seven (around four o'clock).