Old
The word “old” has many usages in English, and when translating it into Japanese, great consideration must be taken into how it will ultimately be expressed, as a one-to-one equivalent word does not exist. First, consider the following phrases, which all have some phrase in the Japanese that translates as “old.”
1. 年とった政治家は堪え性がない。
Old politicians don’t have endurance.
2. 年老いた犬を介護し、最後を看取る。
To care for an old dog and watch its final moments.
3. 義父が老人ホームに入りたがらない。
My father-in-law does not want to enter the nursing home (lit. “elder home”).
4. 老人を尊敬しないといけないことは肝に銘じている。
Respecting the elderly is engraved in me.
5. カシの老木を伐採する。
To cut down old oak trees.
6. 20歳になると、成人になる。
You become an adult when you turn twenty years old.
7. 夜が更けた。
The night grew old.
8. お子さんはおいくつですか。
How old is your child?
9. 古い木造の家が全焼した。
An old, wooden house completely burned.
10. 昔からの慣習を重んじる。
To respect old traditions.
11. 前の彼氏にばったり出会った。
I came across my old boyfriend.
Years Old
Expressing years old (年齢) will differ depending on what you are describing. The first question to ask yourself is whether the thing in question is a living thing or not.
While the age of living things (people, animals, etc.) is expressed with the counter ～歳・才, for non-living entities such as the Earth (Ex. 15), ～年 may be used instead.
12. 享年1８０歳でした。
(They) were 80 years old at passing.
13. 猫は何歳まで子猫で、いつから成猫になるのでしょうか。
Until what age is a cat a kitten, and from when is a cat an adult?
14. 海外在住の人が日本で里帰り出産する場合は、海外に戻るのにゼロ歳の赤ちゃんのパスポートが必要です。
In the case of people abroad who come home to give birth in Japan, a passport is needed for the zero-year-old child for returning overseas.
御年８０歳
15. 地球（の年齢）は｛何歳・何年｝ですか？
How old is the age of the Earth?
While ～歳・年 are both acceptable in Ex. 142, the answer to this question will almost certainly utilize ～年, as the Earth is ultimately not a person. A similar issue arises with trees and similar inanimate yet living things. While ～年 is more prevalent, plant age is often described with ～歳. It is also worth noting that for inanimate objects, age is often not described with the word “old” even in English (See Ex. 17’s translation).
16. 世界で最も古い樹齢５０６３歳の木の生態について詳しく説明していきたいと思います。
I would like to explain in detail about the ecology of the world’s oldest tree, which is 5,063 years old.
17. 苔は寿命が無いとも言われるが、厳密にいうと、何十年も生き続けることができる。
It is often said that moss has no lifespan, but strictly speaking, moss can live for decades.
Months Old
When describing age in months (月齢), the counter ～か月 can be used unproblematically for arguably anything.
18. 生後310か月の赤ちゃん
10-month-old baby
19. 誉君が10か月(歳 △4）になりました。
Homare-kun is now 10 months!
Weeks Old
Weeks old (週齢) is rarely encountered measurement, but its most practical application is for describing the age of fetuses and infants. In more conversational contexts, 齢 will be dropped from ～週齢 (Ex. 22).
20. 妊娠２０週齢の胎児の行動を４Dエコーで観察した。
(We) observed the behavior of 20-week-old fetus(e) with 4D ultrasound.
21. 少なくとも8週齢になるまで仔犬・仔猫を親から引き離してはいけない。
One mustn’t separate puppies/kitties from their parents until they are at least 8 weeks old.
22. 犬は3～12週、猫は2～7週が最も大事な社会化の時期だと言われている。
The most important socialization period for dogs is between 3~12 weeks of age, while for cats it is between 2~7 weeks of age.
Days Old
While days old (日齢) is not so frequently applied to people, but that is a matter of practicality. In situations like how old animals are, it becomes far more practical.
23. 孵化後120日令5前後で小さな卵を生み始め、200日令前後で産卵率はピークに達します。
24. 生後56日齢以下の犬猫の販売等は禁止されています。
The sale of dogs and cats under 56 days of age is prohibited.
25. 虱の成虫１０頭を入れて２４時間産卵させ、０～１日齢卵6を準備した。
(We) placed 10 adult lice (in the container) and had them lay eggs for 24 hours, thus preparing 0- to 1-day-old eggs.
Weeks/Minutes/Seconds Old
The terms 時（間）齢 (age in hours), 分齢 (age in minutes), and 秒齢 (age in seconds) all exist, but they are not encountered outside of specific, academic contexts in which such demarcations may have more utility.
Paraphrasing for “Age”
Besides “age in years,” many of the units we have seen seldom get used in the spoken language. Instead, descriptive paraphrases are more common.
26a. 彼の母親は、彼がわずか5時間だった齢に亡くなった。△
26b. 彼の母親は、彼が生まれてわずか5時間後に亡くなった。
26a. His mother died when he was only five hours old.
26b. His mother died only five hours after he was born.
27. 分裂して3秒後の菌
Three-second-old bacteria → bacteria three seconds after splitting
28. 13日培養された菌
Thirteen-day-old bacteria culture → Bacteria cultured for thirteen days
29. 1日経過したパン
Day-old bread
30. 3日経ったウニ
Three-day-old sea urchin(s)
31. 産卵から5日たった卵を茹でる。
To boil five-day-old eggs since being laid.
32. 作ってから2日目のカレー
Curry made two days ago
33. 妻の車は買ってから5年たっている。
My wife’s car is five years old/of five years.
It has been five years since my wife bought her car.
As for how one would go about describing the age of structures, the verbs 建つ・建てる for “to be built/build” may be used in conjunction with ～前に in the sense of “ago.” Otherwise, ＃年 can be preceded with the prefix 築～.
34. 100年前に建てられたホテル
A hotel that was built 100 years ago
35. 300年前に建った家だ。
This is/it’s a house built 300 years ago.
36. 築50年のマンションに住んでいます。
I live in a 50-year-old apartment.
For things made, ～年物 “years old” and ～年代物 “dated (from)” are noteworthy when expressing “age.”
37. 結婚１０周年なので、奮発して10年物のワインを購入しました。
To celebrate our 10th wedding anniversary, we splurged and bought a 10-year-old wine.
38. 80年物のリーバイスのデニムジャケットを売りたいのですが、どこで売れば1番高く買い取ってくれるでしょうか？
I want to sell an 90’s Levi’s denim jacket, but where can I sell it to get the highest price for it?
This, however, would not be a word that you would just use in conversation. The spoken language must have ways to go around this. With this in mind, consider the following. These examples show how Japanese takes close detail to the total semantic context.
- 享年 counts the age of someone from the moment of conception. As such, the person referenced in Ex. 12 may have potentially only been 79 years old at passing. ↩︎
- The use of the counter ～歳 to describe the age of the Earth is a case of personification. ↩︎
- 生後 often accompanies ages of infants before the number, literally meaning “since birth.” ↩︎
- Some speakers would add 歳 to equate the mile stones of months for their child in the same way they as if they were having a birthday. ↩︎
- 齢 is frequently abbreviated to 令. ↩︎
- Eggs are not exclusively from chickens, as is made evident by this example. Speaking of chicken eggs, though, given that the viability of chickens eggs is between 3-5 weeks on average, it is unlikely that the age of eggs is ever going to be mentioned in conversation, as opposed to their expiration date. ↩︎