This is the 4839th most frequent Arabic word.
الحين
"الحين" means "now" or "currently."
In this sentence, 'الحين' indicates the present moment in which the action has occurred.
الدرس بدأ الحين.
The lesson started now.
Here, 'الحين' is used to transition between past and present states.
كنت مشغول الحين خلصت.
I was busy; now I am done.
'الحين' in this context specifies the current time as being for a particular event.