A record in a database represents a single, uniquely identifiable entry that can contain one or more values in fields. It is equivalent to a row in a table within a relational database. Option 'Comprehensive data types encompassing a single entry' is incorrect because it does not accurately represent the idea of a record, which is an entry, not a data type. 'A placeholder for future data' is also incorrect as records contain actual data, not placeholders. 'All data within a database' is not correct because a record is just one entry among potentially many within a database.