Overseas province
Overseas province (es,pt:província ultramarina) was a designation for territorial entities of Spain, and Portugal where it was established by the Estado Novo.
"Not colonies"
The political regime of Salazar and Marcelo Caetano argued that these territories were not colonies, but rather an integral and inseparable part of Portugal, regarding it as a "nation multirracial and pluricontinental" entity.
Portuguese case
In the case of Portugal, it was an administrative division created by the Portuguese Estado Novo and a designation assigned to the Portuguese colonies -- Angola, Guinea, Mozambique, Sao Tome and Principe, Cape Verde, Macau, the Estado da India (State of India) and Timor.
In the Estado da Índia
The first colony awarded this designation was the Estado da India (State of India) in 1946 as a political way to avoid the pressure Portugal was facing in international fora on being considered a colonial power.
In 1946, 1961
The other Portuguese colonies gained this designation in 1951, thus abolishing the concept of a "Portuguese colonial empire". This designation appeared due to the rethinking of the Conceito Ultramarino Português ("Overseas Portuguese") concept and the consequent emergence of a new Ultramarina Portuguesa ("Overseas Portuguese") policy and the idea of a Solução Portuguesa ("Portuguese Solution").
Loses meaning
In 1975, this designation has lost its meaning after the Carnation Revolution, because all Portuguese colonies, except for Macau, became independent of Portugal. Macau came to be called the "Chinese territory under Portuguese administration", a name which lasted until 1999, when Macau, the last Portuguese colony, was transferred to the sovereignty of the People's Republic of China.