one

Compared meaning: the number one (noun).

比较义项：数量“一”（n.）。

• one 本词

  The plain cardinal number for the quantity 1; a neutral pronoun or determiner, the everyday way to state a count with no extra emphasis.

  基础基数词“1”；用作中性的代词或限定词，是表达数量时最普通、不带强调意味的说法。

  She has one brother and two sisters in her family.

  她家里有一个哥哥和两个姐妹。

• single

  Emphasizes that there is only one and no more, often stressing smallness or limitation; usually a determiner before a noun, rarely standing alone as a pronoun.

  强调“只有一个，不多”，常带有渺小或受限的意味；通常放在名词前作限定词，很少单独作代词使用。

  He lived alone in a single small room for years.

  他多年来独自住在一间狭小的房间里。

One and single both can mean the number one. One is the plain cardinal number, used as a pronoun or before a noun. Single stresses there is only one, usually before a noun, rarely alone. Single also means 'not married' or 'one-way'; not compared here.

这两个词都能表示“一”，容易混用：one 是最普通的基数词，可直接作代词或修饰名词，不带强调意味；single 则强调“只有一个，不多不少”，常用于 “a single + 名词” 的结构，语气更正式、更突出数量之少。这里不比较 single 表示“单身的”“单程的”等其他义项。