A grammatical indirect object: the recipient or beneficiary of an action, typically marked in Japanese by particles like に or へ (e.g., 'to him' in 'I gave him a book').
私は彼に本をあげた。ここで「彼に」が間接目的語で、「本」が直接目的語です。
I gave him a book. Here '彼に' is the indirect object and '本' is the direct object.
先生が学生に英語を教えた。『学生に』が間接目的語の例だ。
The teacher taught English to the students. '学生に' is an example of an indirect object.
彼女に手紙を書いた。日本語では『〜に』で間接目的語を表すことが多い。
I wrote a letter to her. In Japanese, indirect objects are often marked with 'に'.