The Chinese word for one is
一

yī

Chinese Definition

one
1. 數詞
2. 一，大寫壹
3. 阿拉伯數字為 1

Translations for one and their definitions

一
1. one
一長一短 - yī cháng yī duǎn - one short and one long
一死一傷 - yī sǐ yī shāng - one dead, one injured
一高一低 - yī gāo yī dī - one high and one low
一天一夜 - yī tiān yī yè - one day and one night
一日一夜 - jat1 jat6 jat1 je6 - one day and one night, C
一左一右 - yī zuǒ yī yòu - one left, one right
2. each; every
給他們一人一顆蘋果。 (Gěi tā men yī rén yī kē píngguǒ.) - Give them an apple each.
3. single; alone
獨自一人 - dúzì yī rén - a solitary person, one person
專一 - zhuānyī - single-minded, monogamous
4. whole; entire; all: throughout
他們在海灘上玩了一下午。 (Tāmen zài hǎitān shàng wán le yī xiàwǔ.) - They played the whole afternoon on the beach.
5. same; identical
大小不一 - dàxiǎo bùyī - not having the same size
大細不一 - daai6 sai3 bat1 jat1 - not having the same size, C
6. (classical) another; alternative
蟋蟀，一名促織。 (Xīshuài, yī míng cùzhī.) - Crickets, also called cùzhī lit. another name being cùzhī.
7. (formal) certain aforementioned
「旋律」一詞中的「旋」字 - “xuánlǜ” yī cí zhōng de “xuán” zì - the character (m-lite, zh, sc=Hani, 旋) within the word m-lite, zh, sc=Hani, 旋律
8. With the verb modified reduplicated, expressing the transience of the verb:
9. Indicating that the action has occurred only once
10. 看一看 - kàn yī kàn - to have a look
11. 望一望 - mong6 jat1 mong6 - to have a look, C
12. Indicating the intention to try
13. 算一算 - suàn yī suàn - to try to calculate it
14. 計一計 - gai3 jat1 gai3 - to try to calculate it, C
15. once; as soon as; upon
一到 OP 就卡。 (Yī dào OP jiù kǎ.) - It slows down once I get to the opening.
我一拍了照片，她就立即成為眾人矚目的焦點。 (Wǒ yī pāi le zhàopiàn, tā jiù lìjí chéngwèi zhòngrén zhǔmù de jiāodiǎn.) - As soon as I took a picture, she ran towards the limelight.
一見如故 - yījiànrúgù - to hit it off
一至於此 - yīzhìyúcǐ - How did things ever get so far?
16. (gay slang) top
一號 - yīhào - a top
17. (Cantonese, argot, euphemistic) to die
18. =====Usage notes=====
19. (music) Kunqu gongche notation for the note low ti (7̣).
20. one
21. each; every
22. whole; entire; all
23. (Beijing) one
24. =====Usage notes=====

壹
1. (Classical) faithful; committed
2. (financial) one, variant of 一

自己
1. pron. self; oneself
逃離自己的祖國 - to flee one's home country
維護自己的權益 - to uphold one's rights and interests
為自己的錯誤辯解 - to be on the defensive about one’s mistakes
成chéng為wéi 一個更好的自己 - to become a better person; to become a better version of oneself
一個愚昧的人總以為自己是對的。 - Ignorant people always believe they are right.
最終我們都活成了自己討厭的樣子zi。 - In the end we all lived to become people we despised.
食死自己 - to "eat oneself to death" (endanger oneself with eating habits)
2. usage. In Mandarin Chinese, 自己 is a reflexive pronoun. The antecedent it refers to can be inferred by context, which is generally the subject of the sentence.
3. adv. by oneself
自己拿吧！ - Help yourself!
要喝茶自己倒dào 啊。 - If you want some tea, help yourself.