Glossary of Terms

Disclaimer: These definitions is my understanding of terms used in this story based on research.  I'm happy to stand corrected :)

Manga category that represents heterosexual romance stories targeted for girls. The stories are typically innocent, cute and sweet. The amount of sexual content is usually limited to a sweet kiss on the lips.  It focuses more on the relationship building of the two main love characters.
Just as we formally call ourselves Mr. or Mrs.  followed by our surnames in the western world. Honorifics is similar. It’s the Japanese way of addressing a person respectfully.  It’s usually in the form of a person’s surname followed by a suffix representing the person’s status (e.g., Kita-kun).
Nii or Onii is the respectful term for your brother. Adding the san on the end is respectfully acknowledging your older brother.

Aniki  is another term to define your brother.  Generally used if you're blood related or if you're part of the Yakuza :)
Nee or Onee is the respectful term for your sister. Adding the chan on the end is endearingly acknowledging your younger sister.

Aneki is another term to define your sister.
Is the term indicating a teacher or master expert.
It’s a term said before you begin eating a meal.
Hontōni gomennasai
Really very sorry
Gomen nasai
I’m sorry
Is a person who is cold and hostile on outwards appearance but has a really caring and gentle heart.  Midorima Shintaro is an example of this type of person.
A person who is into gadgets, anime and manga.  I'm not exactly sure of the word's definition but my understanding, loosely put, it refers to someone who enjoys their own company. It became a term to describe gadget crazed and anime/manga obsessed people down the track.
A senior. Typically someone of higher rank or experience as yourself in a given field (e.g, school peers, work colleagues etc).  They're not necessarily a master expert but just someone older than you that you see as your 1-Up
Opposite of Senpai. Typically a junior of a given field.  Another term to define this word is "rookie".
I've read is quite common place. It's used to match-up people of a similar or high social standard and ensure a solid family background and good financial prospective. I personally don't know anyone who's gone through an arranged marriage but I guess it takes out a lot of the hard work finding your match. Especially, when you need to focus on working hard and earning the money.  It's a lot different to gōkon blind date group thing that is usually hooked up through mutual friends and yada yada.
Salary Man 
Term to describe an office worker.
I found a fact about the name Shouta , a while back that I thought would kind of suit the whole rumor situation.

Boy x boy love between two males w/ a distinct age difference...

Although, all I can say is "boundaries dude".  There's love and there's weird love that makes your skin crawl and stomach churn.
Not exactly sure of its actual meaning. It's something you'd say before you get stuck into a meal.  It loosely means, "I receive" or "let’s eat". Something similar to saying grace.
Actually is a slang for someone who is trouble. They could be a gang member, delinquent, thug... etc
Is an honorific showing respect for your master.  Someone like a president, CEO...etc is likely to be titled "sama". It can also be referred to someone you serve under.
Formally acknowledging your father.  Informal term is "Otōsan".
Boys love with the extra smexy
Shounen Ai
Boys love that focuses on the story and development between characters
Heart beat sound