Can もらう mean to keep?


While studying I came across this short 会話{かいわ}：

> A: この本をもらってもいいですか？  
>  B: ええ、いいですよ。どうぞ。

A was translated as: "Can I keep this book?" Now, I've learned that もらう means
to receive (something). I would have thought that another word would be used
for "keeping" or "taking ownership" of another object. Am I wrong?




Though もらう does have a similar meaning to "receive", that doesn't quite tell
the whole story. Used as a normal verb (not an auxiliary) as in your example,
the most [first two definitions] are as follows:

>   1. **贈【おく】られたり頼【たの】んだりして受【う】け取【と】り、自分【じぶん】のものとする。**
> 「金【かね】を―・う」「便【とよ】りを―・う」「賞【しょう】を―・う」「元気【げんき】を―・う」「勇気【ゆうき】を―・う」
>
>   2. **頼【たの】んで手【て】に入【い】れる。得【え】る。** 「許可【きょか】を―・う」
>
>

The most important part of these definitions is (in my opinion) 「自分のものとする」 (to
make something one's own). So although the meaning of "receive" is certainly
included in there, it also overlaps with "take", "accept", and "acquire".

In this particular instance, the question 「もらっていいですか」 is asking if it is
really to accept the book, i.e. to make it A's own.

