Semantics
Сейчас я буду мерить вам давление. Сожмите руку в кулак и не разжимайте, пока я вам не скажу.
Now I'm going to check your blood pressure. Clench your fist, and don't release it until I tell you to.
This entry is concerned with the use of the word кулак only with reference to a part of the human body; it cannot refer to animals.