First Person Point of view is when the story is limited to one character's perspective. The main character shares the story through his eyes and tells the story with his voice, such as "I kissed the apple."
Third Person Limited Point of View is when the story is shared in the third person but by only one character's eyes. The story is told by one character throughout, such as "He kissed the apple."
Third Person Omniscient Point of View is when the story is told from various characters eyes, one at a time.
Omniscient Point of View is when the author's voice tells the story. The story is told from a non-character's eyes who sees all, like the eyes of God.
Head hopping occurs when the writer jumps from one character's thoughts to another in the same scene or paragraph. Unlike omniscient point of view, there is no over arching voice in the story, and the view point shifts without the author signaling the change, such as with a chapter break. It is bad writing, because it impedes the reader from connecting with the main character of the scene. Head hopping is a big NO NO with editors and agents because it breaks the reader's intimacy with the story.
And yet, head hopping is found in popular fiction. Nora Roberts, New York Times Bestselling Author, with over 200 titles to her credit, uses head hopping frequently. Here is an example from "Born in Shame."
“Fine. Forget it.” And go away, she thought irritably.
“I’m thinking it’s your eyes.” He knew it was more. He’d known exactly what is was the moment he’d looked over and seen her.
I pointed to works by Nora Roberts and wondered, if Nora Roberts can do it and be accepted by readers, why can't I? What I had to learn was established writers can get away with head hopping, but new writers cannot. This was frustrating for me at first, because I write romance, and often in a scene I would like to reveal both character's thoughts. I had to learn that if I want to attract the attention of a publisher, I can not head hop.
If someday my following is as large as Nora Roberts, I may get away with shifting point of view. In the meantime, no head hopping is my rule. It was a lesson learned.