If you have been perceptive, you may have picked up on some of the patterns. Let's look at the following examples:
DETERMINATION OF GENDER
Masculine---When? Feminine---When?
gato= cat ends in "o" rapariga=girl ends in "a"
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cão=dog, ends in "ão" when in*simple, down-to-earth, and usually monosyllabic words, e.g. mão, hand; melão, melon.
paixão=passion most words ending in -ão are feminine, and usually they are complicated words or abstract nouns, e.g. explosão, explosion; confusão, confusion.
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rapaz= boy/homem=man/fóssil = fossil ends on a consonant (mostly m, l, r, z, s, but there are exceptions) maçã=apple/verdade=truth/ coragem=courageends in -ã, -ade,-gem, and -ice (again, there are exceptions, e.g. o divã, the divan).
Words ending with "e" are trickier as they can be both masculine and feminine, e.g. leite (masc.), milk; parte (fem.), part, debate (masc.), debate. With these one must learn by heart and experience.
Now, remember the four sentences I gave in the beginning? Take note again.
O nome do rapaz é Miguel. The name of the boy is Miguel.
O nome da rapariga é Paula. The name of the girl is Paula.
- É um rapaz! (It's a boy!)
- Não é! É uma rapariga! (No it isn't! It's a girl!)

