For the purposes of legal identification and international travel, your "full name" is generally defined as your First Name, Middle Name(s), and Last Name (Surname) as they appear on your government-issued birth certificate or passport. When booking international flights, the "Secure Flight" data requirements mandated by agencies like the TSA often require you to provide your middle name if it is listed on your passport to ensure an exact match with security watchlists. Failing to include a middle name on a ticket when it is clearly present on your ID can sometimes lead to delays at the check-in counter or security checkpoint, although most airlines allow for a degree of flexibility if the first and last names match perfectly. In some cultures where middle names are not used, the "full name" simply consists of the given name and the family name. However, for anyone with a middle name on their official travel document, the safest rule is to include it in the "First/Given Name" field (e.g., "John Fitzgerald") to ensure the most seamless transition through immigration and boarding.