椅子(yǐ zi) - chair in Mandarin

椅子 (yǐ zi) is a chair, the ordinary sit-down kind with a back. It belongs to the big family of household nouns that carry the neutral-tone suffix 子: 桌子 (table), 盘子 (plate), 房子 (house), 鞋子 (shoes). The 子 has no meaning of its own here, it just makes the character into a free-standing noun.

The measure word is 把, not 个: 一把椅子, 两把椅子. 把 is the measure word for things you grip, and a chair gets it because of the back and arms you take hold of. Tables take 张, so a dining set is 一张桌子和四把椅子.

Watch the second syllable. The 子 is toneless, so it is yǐ zi, never yǐ zǐ. Saying a full third tone on both syllables is one of the clearest markers of a beginner, and it also makes 椅子 sound like a listing of two separate characters rather than a word.