橘子的英语单词是 orange或 tangerine。其中，“orange”是一个通用词汇，指代橙子或橘子，而“tangerine”则通常用来指代小型的、味道更甜的橙子，也可以用来泛指橘子。

1. I ate an orange for breakfast.

2. The sunset looked orange and beautiful.

3. I like eating orange.

4. Oranges and tangerines are both popular fruits.

5. A clear, jellylike preserve made from the pulp and peel of the mandarin orange is called marmalade.

根据具体的语境和需要，你可以选择使用“orange”或“tangerine”来描述橘子。