Nouns that are masculine by form
從形式上判斷是陽性的名詞
(i) The vast majority of nouns ending in -o are masculine.
絕大部分以-o結尾的名詞都是陽性的
Exceptions: nouns ending in -ção/-são that correspond to English nouns ending in -tion/-sion; the words mão ‘hand’ and tribo ‘tribe’, and words ending in –o that are abbreviations of longer feminine nouns such as foto ‘photo’ (from fotografia) and moto ‘motorcycle’ (from motocicleta).
例外：以-ção/-são結尾（對應英語上的詞尾-tion/-sion），ão ‘hand’‘手’ 和 tribo ‘tribe’‘部落’，那些以-o結尾的陰性名詞的縮寫，例如，foto ‘photo’‘圖片’ (縮寫自 fotografia)
moto ‘motorcycle’‘摩托車’ (縮寫自motocicleta).
(ii) In addition, nouns with the following endings are masculine: -ão (when referring to a male human being or an inanimate object), e.g. cidadão ‘citizen’, cartão ‘card’;
-dor/-tor, e.g. cantor ‘singer’, traidor ‘traitor’; -ma when the English cognate ends in -m or -ma, e.g. dilema ‘dilemma’, sistema ‘system’.
除此之外，以下面作為詞尾的名詞都是陽性的
以-ão結尾的名詞（當涉及到的是雄性的人類或者是生命的事物時候）。例如. cidadão ‘citizen’‘公民’, cartão ‘card’‘卡片’，
以-dor/-tor結尾的，例如，cantor ‘singer’，‘歌手’, traidor ‘traitor’，‘叛徒’;
以-ma結尾的，英語詞源上以-m 或者 -ma結尾的，例如 dilema ‘dilemma’，‘困境’, sistema ‘system’，‘系統’.