1. born before all other children in a family; eldest

1. the first child born to parents

Examples

• As the firstborn child, she felt responsible for her younger siblings.
• The firstborn son traditionally inherited the family business.
• Their firstborn arrived two weeks early.
• The firstborn often receives more attention from new parents.
• He was the firstborn of five children.
• The firstborn child typically walks and talks earlier than expected.