tank · trough

1. Origins, structure, and basic meaning

• Structure: 槽 has 15 strokes and denotes a container for liquids and similar contents.
• Basic usage: 水槽（すいそう） means a water tank or aquarium; 浴槽（よくそう） means a bathtub.

2. Common pitfalls and similar expressions

• What a container is used for
  • 水槽の水を替える means to change the water in a tank.
  • In 掃除した浴槽に温かい湯をためました, someone filled a cleaned bathtub with warm water.
• Expressing the extent of its size
  • 足を伸ばせるほど広い means wide enough to stretch out one's legs.
  • The possible action before ほど describes the degree of spaciousness.