Bullet
noun
The kanji and the word are exactly the same. That means they share meanings as well.
たま
Remember 球? This is also a bullet shape (remember how bullets used to be round spheres?). These are both similar ideas, though their intent is different, and they share the same reading.
先日、銃の弾のようなかたちの便が出た。
My poop was shaped like a bullet for a gun the other day.