What does it mean to bulkify an Apex trigger, and why is it important?

Bulkifying means writing the trigger so it processes all records in Trigger.new together rather than one at a time. In practice that means no SOQL queries or DML statements inside loops; instead I collect IDs into sets, query once into maps, and perform DML on lists.

It matters because triggers can receive up to 200 records per batch from data loads and integrations, and Apex governor limits cap queries and DML statements per transaction.

Look for concrete patterns: sets, maps, single queries, list DML. Candidates should connect bulkification to governor limits. A pitfall is only testing with a single record.