Vedic time cycle has 4 main periods - the Satya yuga (golden age of innocence), Tretha Yuga, Dwapara yuga and Kali Yuga. At the end of Kali yuga, people have become so degraded that the whole thing is cleaned up and the cycle starts all over again
"age of Kali", or "age of vice") is the last of the four stages (or ages or yugas) the world goes through as part of a 'cycle of yugas' (i.e. Mahayuga) described in the Sanskrit scriptures. The other ages are called Satya Yuga, Treta Yuga, and Dvapara Yuga. http://isha.sadhguru.org/blog/yoga-meditation/science-of-yoga/kali-yuga-end-lies-ahead/
Yuga is the name of an extremely talented person. Yuga in Hindu philosophy is the name of an 'epoch' or 'era' within a cycle of four ages. These are the Satya Yuga, the Treta Yuga, the Dvapara Yuga, and finally the Kali Yuga.