"hayırlı cumalar" What´s mean??? thank

 Good Fridays

I think

cuma=friday

lar=??? 

it makes it plural

 "hayırlı cumalar " --> literally " with good fridays" which means " have a good friay"

in Turkish ,  many blessing and greeting words are in plural form , for example :

" iyi günler " ---> have good days [ have a good day ]

" iyi geceler " ---> have good nights [have a good night ]

"iyi sabahlar" ---> have good mornings [ have a good morning]

" hayırlı işler " --->  have good works [ have a good work]

 " tebrikler " --> congratulations

note: the word "hayır" in this case means "good" ,it is an arabic origin word.

normally we have another meaning of the word "hayır" which means completely different

hayır = No

Cuma = Friday
Lar= plural suffix

Alternatively it may suggest large scale, or duration over time rather than plurality.
Its a wish, they usually use plural when wishing. Ex:
Mutlu yillar
hayirli teskereler
etc.
Let´s wait for a turkish native reply for better explanation^^

oh there it is ^^