Final answer:
trigger.newMap and trigger.oldMap are used in Salesforce Apex triggers to represent maps of the new and old versions of records being processed, allowing for comparisons and other operations.
Step-by-step explanation:
trigger.newMap and trigger.oldMap are used in Salesforce Apex triggers, a programming construct that allows you to perform custom business logic before or after changes are made to records in the Salesforce platform.
trigger.newMap represents a map of the new versions of the records being processed by the trigger, where the key is the record ID and the value is the new record. trigger.oldMap represents a map of the old versions of the records being processed, where the key is the record ID and the value is the old record.
These maps can be used to compare the old and new values of the records, perform validation checks, and perform other operations based on the changes made to the records.