You know, you're helping me answer a big question about where to go after I finish my tree. I was planning on using the Delights of Learning Turkish. But if I'm planning on one day being able to understand some movie or TV show, then I should maybe focus on conversational now. I can take a class in that starting next month.
But I do very much recommend a text. It's Conversational Turkish by Aarssen, Jeroen.; Backus, Ad. It's better than just a phrasebook of tourist Turkish. Might be a good course after DuoLingo Turkish.
See? We all help one another!
Okay, then. 'Asır' is the interchangable with 'yüzyıl' one being from Arabic and other being derived word. But an asır(century) is a long time that can be considered as an age(not technically of course). So it improved a usage as 'period'.
But its basical meaning is century.