Chinese Ordinal Numbers & Sequencing — 第/初/号/首先/其次/最后

Ordinal numbers (序数词 xùshù cí) answer the question "which one in order?" — first, second, third. English needs suffixes like -st, -nd, and -th (first, second, third); Chinese is far simpler: put 第 (dì) directly before a number. 一 "one" becomes 第一 "first", and 二 "two" becomes 第二 "second".

Sequencing words (次第词 cìdì cí) order steps and events in speech: 首先 "first of all", 其次 "next / secondly", 然后 "then", and 最后 "finally". These are the connective tissue of any explanation, recipe, or story.

Both are HSK 1–2 essentials that you use every day: 第一天 (the first day), 第一次 (the first time), 二号 (the 2nd of the month), and 首先…然后…最后… (first…then…finally).

第 (dì) is the ordinal prefix. Place it directly before a number: 第一 (first), 第二 (second), 第三 (third), 第十 (tenth), 第一百 (hundredth). The number itself never changes form.

Use 第 + number + measure word + noun: 第一个学生 (the first student), 第二天 (the second day), 第三本书 (the third book). The measure word still sits between the number and the noun, exactly as in a cardinal count.

第 also builds sequence nouns: 第一次 (the first time), 第一名 (first place), 第一课 (lesson one). Say 第一次 for "the very first time" and 得了第一名 for "won first place".

Never drop 第 when you mean an ordinal. 一 is just "one", but 第一 is "first". 他是第一 means "he is first"; 他是一 is meaningless.

For dates, "the Nth of the month" uses 号 (hào) in speech: 一号 (the 1st), 二号 (the 2nd), 十五号 (the 15th), 三十号 (the 30th). 今天几号？ — "What is the date today?" 今天五号 — "Today is the 5th."

日 (rì) means the same but is formal or written: 五月一日 (May 1st) appears on official documents and calendars, while everyday speech prefers 五月一号.

号 also means "number" in IDs and rooms: 房间号 (room number), 手机号 (phone number), 几号房间 (which room). In this sense 号 is a noun, not an ordinal prefix.

初 (chū) marks the first ten days of the month in the lunar calendar and some fixed dates: 初一 (the 1st), 初二 (the 2nd), 初三 (the 3rd) … up to 初十 (the 10th).

初 is also used for middle-school grade years: 初一 (7th grade, first year of middle school), 初二, 初三. This is distinct from 第一 — you cannot say 初一 to mean "the 1st" of any month; it is limited to lunar dates and grade levels.

Distinguish the three: 初一 (lunar day or grade), 一号 (day of the month), and 第一 (generic "first"). Context tells them apart.

首先 (shǒuxiān) means "first of all / firstly" and opens a sequence: 首先，我们先吃饭 — "first, let us eat". 其次 (qícì) means "secondly / next" for the middle steps. 然后 (ránhòu) means "then" and links steps naturally. 最后 (zuìhòu) means "finally / last" and closes the sequence.

The full chain is 首先…其次…最后… — "firstly…secondly…finally". Example: 首先学声母，其次学韵母，最后学声调 — "first learn initials, then finals, finally tones."

然后 is the most common everyday connector: 先吃饭，然后睡觉 — "eat first, then sleep". 先…然后… is a lighter, more casual sequence than 首先…其次…最后….

最后 also works as a noun meaning "the last one": 最后一个 (the last one), 最后一天 (the last day), 最后一名 (last place).

Ranking uses 第 + number + 名 (place): 第一名 (first place), 第二名 (second place), 第三名 (third place). To ask "what place?", use 第几名.

倒数 (dàoshǔ) means "counting from the end": 倒数第一 (last place), 倒数第二 (second from last). 他考了倒数第一 — "he came last in the exam."

Do not confuse 第一名 (first place / rank) with 第一个 (the first one / sequence). 名 = rank, 个 = item.

Do not omit 第 when you mean an ordinal. 他是第一 ("he is first") is very different from 他是一 ("he is one") — the latter is meaningless.

Do not use 初 outside its two special uses. 初 only marks 初一–初十 (lunar days) and 初一–初三 (middle-school grades). For any other ordinal use 第.

Do not mix 号 and 日 in register. 号 is spoken, 日 is formal or written. Saying 五月一日 is fine in writing; in casual speech 五月一号 is more natural.

Do not forget the measure word after 第 + number: 第三个 (the third one), not 第三 alone before a noun.

Do not drop 最后 when closing a list — a 首先 without a matching 最后 leaves the sequence hanging.