孫

1. Origins, structure, and basic meaning

• Structure: 孫 (まご) is a kinship noun for a child of one’s child, without specifying gender.
• Basic usage: In 孫と遊ぶ, the grandchild is a companion in the activity; in 孫から届いた手紙, the grandchild is the source of the letter.

2. Common pitfalls and similar expressions

• Companion と and source から
  • 孫と marks the companion in the park, whereas 孫から marks who sent the letter to the grandmother. Changing the particle changes the grandchild’s role in the event.