IPA: /ʌnˈtʃɑːrtərd/
KK: /ʌnˈtʃɑrtərd/
Not mapped or explored; referring to areas or situations that are unfamiliar or not previously documented.
The explorers set out to discover unchartered territories in the remote jungle.
Unchartered → It is formed from "un-" (meaning not) and "chartered" (from Old French *charter*, meaning a document or grant). The word "unchartered" means not having a charter or not officially documented, often referring to areas that are not mapped or explored.
Think of 'not' ('un-') having an official 'document' or 'grant' ('chartered') — that's why unchartered refers to places that are not officially documented or mapped.