He was very helpful in resolving the issue as our mediator.

They (referring to women or girls) are my best friends.

He is very careful in his choice of diction.

At his funeral, I read a eulogy for him.

A determiner plays a role in specifying a noun.

That person is my friend.

He is very careful in choosing words and phrases.

The language used by courtesans during the Edo period, that's what 'Kuruwa Kotoba' is.

The word 'hatarakikotoba' is used in this old document.

There are several words used as 働詞 in this ancient document.