The term 'passports, for instance' can be summarized by the three-letter acronym IDS. IDS stands for Identification Documents, which are documents used to prove a person's identity. Passports are one of the most common forms of identification documents, and are typically issued by a government to its citizens. They are used to verify a person's identity when traveling abroad, and are also used for other purposes such as applying for visas or other official documents.