の玉

a ball or spherical lump of [something]

→ の

phrase Rare #33,752

a ball or spherical lump of [something] 玉 refers to a rounded, ball-like object; the word before の tells you what it is made of or associated with.

JA: ガリレオは二つの鉄の玉を塔のてっぺんから落とした。

EN: Galileo dropped two iron balls from the top of the tower.

Fireball

— RRR (2022)

Galileo dropped two iron balls from the top of the tower.

Is this silver ball okay?

— 生きる (1952)