How do we extend 第二天 ("next day") to other days ("previous day", "same day", etc.)?

Question

第二天: next day / the morrow

I find this a versatile and useful word, and wondering if it can be extended to "same day" and "previous day" versions. There is this discussion at ChinesePod:

JP: 那么，今天是“第一天”，是吧？
JZ: 对。
JP: 第二天就是明天。
JZ: 没错。所以这个“第二天”形容的就是明天，啊。
_{(JP: John Pasden; JZ: Jenny Zhu)}

However, I've never seen 第一天 used to mean "same day", it usually means "first day":

今天是我第一天上班。 "This is my first day at work."

So I'm not sure if 第一天 also means "same day". I don't think 第三天, 第四天, etc., works, but maybe I'm wrong.

It seems 当天 is the suitable word for the "same day", and Google gives examples of 当天配送 = "same day delivery". For "previous day", the CC-CEDICT dictionary gives 隔夜 = "overnight / of the previous day". I'm not sure if this is the best choice, but I found the example 隔夜菜 = "overnight food" = "leftovers". Maybe there is a better way of thinking about all this.

Question: How do we extend 第二天 ("next day") to other days ("previous day", "same day", etc.)?

Answer 1

1. The quoted dialogue is mostly correct. Unlike 明天 (tomorrow), 第二天 (the next day) does not assume when the speaker is at. If 明天 is the day after today, 第二天 can be the day after any date. Therefore, one says sentence 1.1 but not 1.2:

(1.1) 平安夜的第二天便是聖誕節。

(1.2) *平安夜的明天便是聖誕節。

A more literary equivalent of 明天 and 第二天 is 翌日:

(1.3) 門市翌日開張。(=明天 if this is found on a poster posted today)

(1.4) 中秋節翌日是公眾假期。(=第二天)

後一天 is a possible alternative. It is the same as 第二天. But 後天 means the day after tomorrow, and 前天 means the day before yesterday.

2. To say 'the same day', 同一天 is a literal but valid translation, and is more colloquial than 當天.

(2.1) 他的新書在開始發售的同一天便售罄。

(2.2) 他的新書在開始發售當天便售罄。

(2.3) 他的新書在發售第一天便售罄。

I would say all the sentences above have the same meaning, only expressed differently. Sentences 2.1 and 2.2 both mean 'His new book was sold out on the same day he begins selling it.' Sentence 2.3 means 'His new book was sold out on the first day of selling it.'

3. Broadly speaking, to say 'the previous day', we can use 前一天. 隔夜 literally means 'partitioned with a night' and is an adjective in itself; usually it is applied on things that are placed overnight (especially perishable food). Therefore sentence 3.2 is wrong:

(3.1) 他出發前一天便把行李收拾好。

(3.2) *他出發隔夜便把行李收拾好。

(3.3) 吃隔夜菜有損健康。

If you want to say ‘He packed his luggage overnight’, you may want to use 連夜:

(3.4) 他連夜把行李收拾好。

4. 第三天, 第四天, 前兩天, 前幾天 are all valid with the right context.

(4.1) 他第三天便走了。He left on the third day.

(4.2) 他前兩天便走了。He left two days ago.

(4.3) 他前幾天便走了。He left a few days ago.

Answer 2

You have to first understand what "第" means. It's used to point out the position of something from a sequence.
One, two, three, four, five, six: 一, 二, 三, 四, 五
First, second, third, fourth, fifth, sixth: 第一, 第二, 第三, 第四, 第五

So 第二天 isn't completely equal to "next day", but "the second day".

当天: same day (this is correct)

For "previous day", you're basically trying to refer to the "-1" day from today, so "第" cannot be used here...like there's no "negative first" in English.

Only phrase I can think of now is "前一天".
前: before, 一天: one day
so 前一天 = one day before = previous day

Example:
Today is his first day at work, but he started learning some related knowledge the previous day.
今天是他第一天上班, 但是他前一天就開始學習一些相關的知識。

Do keep in mind that 前天 means "the day before yesterday", so don't confuse it with 前一天

Edit:
To reply Wayne's comment.. 隔夜 is most often used as an adjective and pretty much equivalent to "overnight" in English.
You can also use "前一天的菜" to refer to 隔夜菜.

I usually like to prepare lunch the previous day, then bring to work the next day.
我平常喜歡前一天把午餐準備好，然後隔天帶去公司吃。

My girlfriend wants to break up with my because I gave her my leftover food from previous day(yesterday). She thinks overnight food is disgusting.
我女朋友說要和我分手，因為我把我前一天(昨天)剩的飯給她吃。她覺得隔夜菜很噁心。

我平常喜歡隔夜把午餐做好 -> (X) This doesn't sound natural

Answer 3

For relative time in talking/writing:
"前一天", "同一天/当天/第一天", "后一天", "第三天", "第四天", etc.
(supposed to be.)

For current time:
"前天", "昨天", "今天", "明天", "后天"
-2 day, -1 day, 0 day, +1 day, +2 day

今天可以是上班第一天，明天也可以是休假第一天, "第一天" is a relative time, it just depends on how you describe.
(Try to think "后天" is "明天的后一天" )

Plus,
as "明天" and "后天" are used more often in daily life,
use "第二天" instead of "后一天" in writing and speaking to be less ambiguous (with "后天" and "后一天").

Answer 4

次日(the next day) is probably the one you are looking for. It might be a bit archaic, but it's fairly understandable. The word is used in the old story telling sometimes.

E. g. 次日(第二天), 他开到了我家。