1. lines that mark the limits of an area; borders
2. limits or rules about what is acceptable in relationships or behavior

Examples

• The fence marks the boundaries between our property and theirs.
• National boundaries are often disputed in border regions.
• She set clear boundaries with her coworkers about personal topics.
• Parents need to establish boundaries for their children’s behavior.
• The river forms a natural boundary between the two states.
• It’s important to respect other people’s boundaries in relationships.
• The survey team mapped the exact boundaries of the forest preserve.