This is the 552nd most frequent Japanese word.
く
The Japanese word "く" (ku) can refer to: 1. The hiragana character for the "ku" sound. 2. A section, ward, or district in a city (区).
In this sentence, "く" is part of the verb conjugation "くれる", which is used to indicate receiving an action to the speaker’s benefit.
彼は走者を支えるために拍手をしてくれた。
He clapped to support the runners.
Here, "く" appears as the root of the adjective conjugation, such as turning "勇気のある" into "勇気のある人" to describe a courageous person.
彼は本当に勇気のある人だと思う。
I think he is truly a courageous person.
In this example, "く" is part of the verb conjugation "おく", which means to do something in preparation.