1. to increase in size, volume, quantity, or scope
2. to give more details about something; to elaborate

Examples

• The balloon expands when filled with air.
• The company expands its operations to new markets.
• Water expands when it freezes.
• The teacher asked him to expand on his answer.
• The universe continues to expand.
• She expands her knowledge by reading widely.
• The metal expands in the heat.