Nouns that are feminine by form
从形式上判断是阴性的名词
(i) The vast majority of nouns ending in -a are feminine.
绝大部分以-a结尾的名词都是阴性的
Exceptions: nouns ending in -a that denote human beings and can therefore be masculine or feminine depending on the sex of the person referred to; a group of nouns ending in -ma, e.g. problema ‘problem’, pajama ‘pyjamas’; the words alerta ‘alert, warning’, cometa ‘comet’, dia ‘day’, mapa ‘map’, planeta ‘planet’, samba ‘samba’, tapa ‘slap’, among others, which just have to be memorized. Note that nouns ending in stressed a (á) are usually masculine, e.g. maracujá ‘passion fruit’, sofá ‘sofa’, tamanduá ‘anteater’, as are those ending in -ã that denote an inanimate object, e.g. balangandã ‘bauble’, divã ‘couch’, o Irã ‘Iran’, although maçã ‘apple’ and lã ‘wool’ are feminine.
例外：以-a结尾的指示人类的名词，它可以是阳性或者是阴性的，决定于所指向的人物的性别，一些以-ma结尾的名词，例如，problema ‘problem’‘问题’， pajama ‘pyjamas’ ‘睡衣’， alerta ‘alert, warning’警报，提示，cometa ‘comet’ 彗星, dia ‘day’日子, mapa ‘map’地图, planeta ‘planet’行星, samba ‘samba’桑巴, tapa ‘slap’ 掴，诸如此类，都是必须要特别记忆的。需要注意的是，那些以重读(á)结尾的名词一般都是阳性的，例如. maracujá ‘passion fruit’ 百香果，sofá ‘sofa’,沙发，tamanduá ‘anteater’ 食蚁兽，同样地，那些以-ã结尾的指示为无生命的物体也是阳性的，例如balangandã ‘bauble’, 小件装饰品，divã ‘couch’ 睡椅, o Irã ‘Iran’ 伊朗, 尽管maçã ‘apple’苹果 and lã ‘wool’羊毛是阴性的
(ii) In addition, nouns with the following endings are feminine: -dade,1 e.g. lealdade ‘loyalty’; -ção (corresponding to English -tion), e.g. ação ‘action’; -dão (abstract nouns), e.g. solidão ‘loneliness’; -gem,2 e.g. viagem ‘journey’; -ise, e.g. crise ‘crisis’;-ite, e.g. bronquite ‘bronchitis’; -são (corresponding to English -sion), e.g. decisão ‘decision’; and -tude, e.g. juventude ‘youth’.
除此之外，以下面作为词尾的名词都是阴性的
-dade,e.g. lealdade ‘loyalty’;忠诚
-ção (corresponding to English -tion), e.g. ação ‘action’;（那些对应英语-tion结尾的）
-dão (abstract nouns), e.g. solidão ‘loneliness’;抽象名词，例如，孤独
-gem,e.g. viagem ‘journey’; 旅程
-ise, e.g. crise ‘crisis’;危机
-ite, e.g. bronquite ‘bronchitis’; 支气管炎
-são (corresponding to English -sion), e.g. decisão ‘decision’; 决定
-tude, e.g. juventude ‘youth’.年轻时代
1 The word autoridade is used as a masculine noun when it means ‘a (male) government official’.
autoridade通常被用作阳性名词，当它被意为‘一个男性的政府官员’
2 Except the word personagem ‘character’ (in a book, film, etc.), which can be masculine or feminine.
除了角色（在书或者是电影等），它可以是阳性的也可以是阴性的