Proper noun
The standardized spoken Chinese language, also referred to as Standard Mandarin. The term remains in common use in the Republic of China (Taiwan) and colloquially in Hong Kong (along with Putonghua). In mainland China, Guoyu or Taiwan Guoyu is used to refer to Taiwanese Mandarin (standard), as opposed to mainland standard Mandarin.
(historical) The language the Emperor of China spoke.
Source: en.wiktionary.orgFor some linguists of the early 20th century, the Putonghua, or "common tongue/speech", was conceptually different from the Guoyu, or "national language". Source: Internet
The pronunciation of words is a standardization choice and occasional standardization differences (not accents) do exist, between Putonghua and Guoyu, for example. Source: Internet