Originally Posted by
HuangYushi
Qizi 妻子 is the noun for "wife".
Taitai 太太 is, as you said, the title equivalent to "Mrs". You can also use it to refer politely to the mistress of a household or a (presumably) married woman. You hear taitai is modern dramas.
In ancient dramas, the word is furen 夫人, which can be used interchangeably to mean "wife", "Mrs" (when prefixed to be surname), "madame" or "lady" (see the example below).
Example: 这位太太是林雨忠先生的妻子。
[zhe4 wei4 tai4tai shi4 lin2 yu3 zhong1 xian1 sheng2 de qi1 zi3.]
Translated: This taitai [madame/lady] is the wife of Mr Lin Yuzhong.
People use taitai to mean "wife" because they want to sound more polite, just like they use xiansheng 先生 (literally, "Mr") to mean "husband".
btw: Do you have a proper full dictionary besides your pocket one? Pocket dictionaries are convenient, but they tend to be lacking in the full range of uses for words and the corresponding examples.
Finally: Language lessons come with different foci and levels. Therefore, what you learn depends on what your particular language course is about. I teach Chinese for academic use, so the course tends to focus more on reading and writing, but my students can also take an optional course that has a larger speaking component. Written Chinese can be quite different from the spoken one in certain circumstances.
HYS