太る

1. Origins, structure, and basic meaning

• Structure: The written form is 太る, read ふとる. This intransitive verb describes either gaining body weight or a stem or trunk becoming thicker.
• Basic usage: 少し太る concerns a person’s weight, while 幹が太る concerns the increasing thickness of a plant stem.

2. Common pitfalls and similar expressions

• A person gaining weight
  • The person gains a little weight after stopping exercise. Example: 運動をやめてから少し太りました。 — I gained a little weight after I stopped exercising.
• A thicker plant stem
  • The plant is moved to a larger pot after its stem or trunk grows thicker. Example: 幹が太ってきたので、大きな鉢に植え替えました。 — The trunk has grown thicker, so I transplanted it into a larger pot.