passive vocabulary

The words and phrases, collectively, that someone understands in speech and writing but does not commonly use.

Japanese Meaning

受動語彙：聞いたり読んだりして理解できるものの、普段の会話や文章作成では積極的に使われない単語や表現の集合

Although she seldom used them, her passive vocabulary allowed her to understand complex academic texts.

彼女はめったにそれらを使わなかったが、聞いたり読んだりして理解できるが普段はあまり使わない語や表現が、複雑な学術文献を理解する助けになった。

Sense（1）

The words and phrases, collectively, that someone understands in speech and writing but does not commonly use.

John's passive vocabulary seems to encompass most of the words in the Collegiate Dictionary!

passive vocabularies

（ plural ）