Whenever you find a 's to some word like Andrew's or today's it means "belongs to". e.g. This is Andrew's phone = This phone belongs to Andrew same ways "Today's topic is terrorism" = "Topic for today is terrorism" that means this topic is exclusively for today. Hope this will help you. Regards, Ritesh Dayal.

today means the day that includes the present moment ..

It's April 23, one of the national holidays of ours. So no school today. Very meaningful to me.