1. to insert (something) between other things or parts
Usage: formal
2. to add an extra day, month, or period to a calendar
Usage: technical; calendar systems

Examples

• The editor decided to intercalate a new chapter between the existing ones.
• Ancient calendars often intercalated extra days to align with seasonal cycles.
• The researcher intercalated additional data points into the existing dataset.
• February 29th is intercalated every four years in leap years.
• The composer intercalated a brief musical interlude between the main movements.
• Historians intercalate missing dates to complete chronological records.