Language is evolving and online language is doing it at an ever faster rate. This slang and these acronyms (actually they are mainly are mainly initialisms, but who uses that word?) should be known to all the people using Reddit and other social media platforms, except LinkedIn (Facebook, Twitter, Pinterest, Hacker News, Voat, Quora, YouTube, Google Plus, Tumblr, Instagram, VK, Flickr, Vine, Meetup, Snapchat, Periscope, SoundCloud, WhatsApp, Slack, WeChat, Sina Weibo etc.)

subreddit

Reddit entries are organized into areas of interest called “subreddits”. Historically, the front page was the “main reddit”, and other areas were “subreddits”. There is now no main subreddit. Instead, there are multiple default subreddits dealing with topics such as books, television, and music.

karma

Karma is a point system that lets you know how your submissions or comments are doing. The more karma your post has, the more people have upvoted it. Generally a higher karma count on a post means that the community of that subreddit found your post valuable and interesting. Your karma is logged on your user page on the top right. Please note that self-posts earn you no karma. Only comments and link-posts do.

meme

A meme is a shape of thought, an idiom, a shorthand catchphrase — some tiny fragment of pop culture or understanding or psychology that is passed from person to person (either in person or via text, movies/tv, or internet communication methods).

circlejerk

A group discussion or activity between like-minded individuals that validates mutual biases or goals in a non-confrontational environment.

hivemind

Named because Reddit’s majority of users tend to follow clearly and intensely about one issue to an effect that it seems like Reddit is a collective mind on certain issues, expressing it by downvoting certain ideas to oblivion. It is used as a negative term, trying to indicate the conformity or closemindedness of Redditors on those issues. Related to circlejerking.

throwaway accounts

Accounts people make when confessing to a sin, and don’t want to be traced.

Orangered

The term used for the little envelope in the top right corner to let you know you have a message

TIL

Today I Learned

ELI5

Explain Like I’m Five

FTFY

Fixed That For You (used when someone corrects you)

AMA

Ask Me Anything

IAmA

I Am A

ITT

In This Thread

IIRC

If I Recall Correctly

IMO

In My Opinion

AFAIK

As far as I know

DAE

Does Anyone Else

OP

Original Poster

NSFW

Not safe for work

NSFL

Not safe for life

TL;DR

Too long, didn’t read

SO

Significant Other

ಠ_ಠ –

“look of disapproval – used to show shock/disbelief/jealousy