noun
official name of a country
Refers to the formal, legally recognized name of a nation, as opposed to common or abbreviated names.
日本の正式国名は「日本国」です。
The official name of Japan is 'Nihon-koku' (State of Japan).
書類には正式国名を記入してください。
Please write the official country name on the form.
Compound of 正式 (official, formal) + 国名 (country name).