Is the kanji for sister-in-law and step sister the same?


I was wondering if the kanji for both sister-in-law and step sister is 義妹
(younger sister) or 義姉 (older sister) and there's no way of differentiating
them other than context?




If your question is how to tell meaning of 義姉, you need to guess from contexts
in the present-day colloquial language.

Strictly speaking, [義]{ぎ}[姉]{し} or [義]{ぎ}[妹]{まい} only means (or meant) sister-
in-law or sworn sister. Here are definitions in デジタル大辞泉.

> ぎ‐し【義姉】
>
> １ 義理の姉。妻または夫の姉、兄の妻など。
>
> ２ 血縁関係はないが、姉妹の約束を交わして姉としている人。

> ぎ‐まい【義妹】
>
> １ 義理の妹。夫または妻の妹、弟の妻など。
>
> ２ 血縁関係はないが、姉妹の約束を交わして妹としている人。妹分。

In colloquial language, [義]{ぎ}[姉]{し} and [義]{ぎ}[妹]{まい} have taken in the place
of [継]{まま}[姉]{あね} and [継]{まま}[妹]{いも} which mean elder/younger stepsister.

If your question is how to distinguish step sister from sister-in-law, you can
use [異]{い}[母]{ぼ}[姉]{し} (elder sister from a different mother),
[異]{い}[父]{ふ}[姉]{し} (elder sister from a different father) and so on, which
sound very formal.




If your question is how to tell meaning of 義姉, you need to guess from contexts
in the present-day colloquial language.

Strictly speaking, [義]{ぎ}[姉]{し} or [義]{ぎ}[妹]{まい} only means (or meant) sister-
in-law or sworn sister. Here are definitions in デジタル大辞泉.

> ぎ‐し【義姉】
>
> １ 義理の姉。妻または夫の姉、兄の妻など。
>
> ２ 血縁関係はないが、姉妹の約束を交わして姉としている人。

> ぎ‐まい【義妹】
>
> １ 義理の妹。夫または妻の妹、弟の妻など。
>
> ２ 血縁関係はないが、姉妹の約束を交わして妹としている人。妹分。

In colloquial language, [義]{ぎ}[姉]{し} and [義]{ぎ}[妹]{まい} have taken in the place
of [継]{まま}[姉]{あね} and [継]{まま}[妹]{いも} which mean elder/younger stepsister.

If your question is how to distinguish step sister from sister-in-law, you can
use [異]{い}[母]{ぼ}[姉]{し} (elder sister from a different mother),
[異]{い}[父]{ふ}[姉]{し} (elder sister from a different father) and so on, which
sound very formal.

