Sometimes people who are involved in writing talk in what is almost another language, so here is the crib sheet for some of the more common acronyms and words used.
Sub - submission, what you send to an agent or publisher to see if they are interested. Typically a full synopsis and the first three chapters.
Synopsis - the story of your book. What it's about, who the main characters are, when and where it takes place, and most important, the full plot from start to finish. Ideally, your sysnopsis should be written in the same style as your novel, but the important thing is that publisher knows exactly what they are getting.
First draft - what you post on Wattpad. When you finally write "the end" at the bottom and think the story is done. No, that is just your starting point.
MS - manuscript. This could be paper (double spaced, one side of page only, numbered and with big margins. 12 point, black ink and a standard font) or electronic (usually .doc or .rtf)
Editor - the person who goes through your MS and points out all the things you have got wrong and need to fix. She will not do it for you. Instead, she'll give you a date by which you have to return it to her with all problems fixed.
Agent - the person who handles your contracts. His job is to get you the best deal with publishers, not to get your MS accepted or to help you edit it.
MC - main character, the person your novel is about.
LI - love interest, your MC's squeeze.
H&H - hero and heroine.
HEA - happy ever after
HFN - happy for now. Note, HEA and HFN are typical of genre fiction. Literary fiction often involves all the characters dying or living in eternal misery.
IM - internal monologue, what the character feels and thinks. Significant IM is sometimes put in italics but without "he thought to himself".
Pov - point of view. Every scene should be in someone's pov. There should be no sweeping descriptions that don't involve one of your characters. An expert author can switch pov smoothly during a scene, but the reader must always know whose pov it is.
AFP - alternating first person. The pov most popular on Wattpad, and the one most hated by publishers.
Inciding incident - the thing, however small, which starts the problems for the MC and propels him into action and into the story.
Slushies/slush - the enormous pile of unsolicted MSs that are sitting in the office of every publisher and agent waiting for some unfortunate person to go through them. Most offices have at least a thousand MSs in the slush pile and the editor who has to read them is looking for an excuse to reject them without having to keep reading. Most of them will be rejected by the end of the first page.
Unagented sub - unsolicited submissions. Subs that come through an agent go into a different pile.
Royalties - The amount of money you get from each book sold.
Advance - money the publisher gives you when you sign the contracts. Typically one third on signing, one third on production of a completed MS and one third on publishing. It's really a loan against royalties.
Option - the publisher wants the right to get first look at your next book, but is under no obligation to buy it. May tie up a MS for months.
Reversion rights - How long your book has to be out of print (or selling less than a specific number of e-books) before the rights revert to you and you can resell or republish the book.
Feel free to add all the ones I've missed.