This is the 722nd most frequent Greek word.
κεφαλιά
"Κεφαλιά" means "header" (a strike or hit with the head, often in sports like soccer).
In this sentence, 'κεφαλιά' refers to the act of hitting the ball with one's head, commonly used in sports like soccer.
Η κεφαλιά του παίκτη ήταν εκπληκτική.
The player's header was amazing.
Here, 'κεφαλιά' metaphorically describes the top section of the tree, which is its 'head' or 'crown'.
Η κεφαλιά του δέντρου κρίθηκε επικίνδυνη μετά την καταιγίδα.
The crown of the tree was deemed dangerous after the storm.
In this context, 'κεφαλιά' is used figuratively to represent the main point or punchline of a story or joke.