Third person objective is where the narrator doesn't know what any of the characters are thinking. An example of this would be "She looked happy". Notice how the narrator doesn't say that she is happy but rather she only seemed to be happy.
Third person limited is where the narrator only knows how one of the characters is thinking. An example of this would be "He was scared, but he eventually admitted to lying to his mother. His mother seemed to be upset, but told him it was alright." In these sentences, the narrator says that the boy was feeling scared, and they knew that for sure. When it came to the mother, however, the narrator is only able to tell how it looks like she's feeling.
Third person omniscient is where the narrator knows what all of the characters are thinking. An example of this would be "Janet lost the race, and was sad. Pablo, on the other hand, won, and was happy about it". This shows how both of the characters are definitely feeling.
All of these are similar, but definitely not the same. So simply just saying 'third person' when referring to a story's point of view wouldn't really be correct.