1. the line where the earth or sea appears to meet the sky
2. the limit of a person's knowledge, experience, or interest
3. the range of one's perceptions, knowledge, or experience

Examples

• The sun disappeared below the horizon.
• Ships appeared on the distant horizon.
• Travel broadened her horizons significantly.
• The job opened up new horizons for him.
• We could see mountains on the horizon.
• Reading expands your intellectual horizons.
• The horizon stretched endlessly before us.