This is the 849th most frequent Hungarian word.
egyikük
"One of them."
The word 'egyikük' refers to 'one of them' in a negating context, implying 'not even one of them.'
Egyikük sem jött el a találkozóra.
None of them came to the meeting.
The word 'egyikük' is used to specify one of two individuals being referred to.
A két testvér közül egyikük nagyon jól rajzol.
One of the two siblings draws very well.
The word 'egyikük' here signifies 'one among the group' of colleagues mentioned.