The noun 橙子 (chéngzi) refers to the fruit "orange." It is one of the common fruit vocabulary words in Chinese and is typically used in everyday conversation about food and preferences. Note that the color orange is a separate word: 橙色 (chéngsè).
这些橙子又甜又多汁。
zhèxiē chéngzi yòu tián yòu duō zhī.
These oranges are both sweet and juicy.
你帮我买几个橙子回来吧。
nǐ bāng wǒ mǎi jǐ gè chéngzi huílái ba.
Can you buy a few oranges for me on your way back?
冬天的橙子最好吃了。
dōngtiān de chéngzi zuì hǎochī le.
Oranges in winter are the most delicious.