connective N1 uncommon politewritten
ないし（は） — or
ないし（は）
Meaning
① or (alternative): or — either A or B, in formal or written register (= または)
② from ~ to ~ (range): from ~ to ~ / between ~ and ~ — names the two ends of a numeric range
Key sentence
① or (alternative)
電話ないしメールでご連絡ください。
Please contact us by phone or email.
② from ~ to ~ (range)
完成まで三ないし四日かかる見込みだ。
It is expected to take three to four days to complete.
Formation
| Attaches to | Form | Example |
|---|---|---|
| Between two nouns (alternative) or two numbers (range) | N ないし(は) N |
When: Bookish, legal, and administrative writing; ないしは is slightly more emphatic.
Examples
① or (alternative)
本人ないし代理人が署名する。
The person concerned or a proxy will sign.
② from ~ to ~ (range)
参加者は五ないし十名を予定している。
We expect five to ten participants.
Easily confused with
See ないし（は） in real sentences
Jengo shows ないし（は） the way you actually meet it: inside real Japanese sentences, so it sticks instead of staying an abstract rule.
Study it in JengoSources Compiled with reference to A Dictionary of Advanced Japanese Grammar.