The word Vocation originates form the Latin word vocātiō, which means a call or summons. The defention of the word vocation today in the is a strong eeling of suitability for a particular job or career. The religious meaning is a call from God to do our job that God has given us. People believe in life that they dont have a life  calling, or dont feel compelled to do a certain job in life, the truth is that everyone is givent a vocation in life to follow and that everyone in the world has a purpose given to them by God, and all you need to do is search a bit to find out your true vocation. 

These are two famous quotes about vocations that may get you to undersatnd the meaning of vocation more:

 

Everyone has his own specific vocation or mission in life; everyone must carry out a concrete assignment that demands fulfillment. Therein he cannot be replaced, nor can his life be repeated, thus, everyone's task is unique as his specific opportunity to implement it.

Viktor E. Frankl

 

Many people mistake our work for our vocation. Our vocation is the love of Jesus.

Mother Teresa