As an acknowledged expert on the intersection of sex, relationships and technology, I sometimes find myself conversing in what sounds like a foreign language. In fact, a few weeks ago I was explaining to a group of fellow clinicians the need for them to understand what it means when a client looks at them and says something like:

"I was doing J-Date on the DL and my wife didn't know because I kept it to sexts and iCU2. But then I scoped AM and suddenly I was IRL with every MILF in town. Now I'm a walking STD. Plus, I've got this cyberstalker chopping bunnies in my kitchen. Seriously, she's tweeting my sexts and digits all over town and I'm totally not ROTFL because my wife is catching on. She even put a Net Nanny on my Droid."

Most likely, if you're at all involved with life online, you deciphered at least the basics of this individual's situation -- he's cheating on his wife, one of his girlfriends is doing a modern-day impersonation of Glenn Close in Fatal Attraction, and his wife is catching on to the fact that he may not be holding up his end of their marital fidelity pact. But were you able to decode the entirety of his statement? If so, I'm impressed, and you should definitely feel free to read something else now. If not, you're hardly alone. To help, I've compiled a list of sexual and romantic terminology commonly used in online sexual and romantic interactions, creating an abbreviated "sexicon," printed below. (This material is pulled primarily from my recently released book Closer Together, Further Apart, coauthored with Dr. Jennifer Schneider.)

*Apps: Apps are software that can be downloaded onto smartphones and other digital devices. Apps can help users find restaurants, play games, listen to music, access porn, find a sexual partner, etc.
*Adult Friend Finder App: These apps are "friend finders" in name only. In reality, they are used to facilitate casual and/or anonymous sexual hookups.
*A4A (Adam4Adam): This is a website and app used by gay men for both dating and casual sexual hookups.
*AM (Ashley Madison): This is a website and app for married people looking to cheat
*Bang With Friends: This app, popular with young adults, helps people determine which of their Facebook friends might be interested in no-strings-attached sex.
*Blendr: This is an adult friend finder app used by straight people for casual sexual hookups.
*Chatroulette: This is a video chat site that randomly pairs strangers for web-based interactions. The site is popular with online exhibitionists and voyeurs.
*Cyberstalking: This is the deliberate, repeated, and hostile use of digital technology to harm, frighten, or otherwise harass another person.
*Digits: Digital contact information, such as phone number, e-mail, and website address.
*The DL: This is shorthand for "on the down-low." Initially this term was used in reference to gay or bisexual men who were in a primary relationship with a woman but sought male-on-male sex on the side, without their wife's or girlfriend's knowledge. In recent years, use of the term has expanded. Now it refers to any secretive sexual activity.
*FaceTime: This is a video chat service allowing one-to-one video calls between Apple users.
*Grindr: This is an adult friend finder app used by gay men for casual sexual hookups.
*Hookup Apps: This is another term for "adult friend finder" apps.
*iCU2: This is a video chat site often used for sexualized webcam exchanges.
*Instagram: This is a photo sharing service that lets users take pictures and share them on social media sites.
*IRL: This is digital shorthand for "in real life," as in: Do you want to hook up IRL?
*MILF: This is shorthand for "Mom I'd Like to F***."
*Newsgroups: These are advanced electronic bulletin board systems. Newsgroups are not as popular as they once were, but they are still used to post illegal sexual content.
*Omegle: This is a video chat site that is often used for sexualized webcam exchanges.
*PNP: "PNP" is short for "party and play." This designation is used on dating and hookup sites and apps to indicate a desire for drugs (usually meth or cocaine) paired with sex.
*PTP: "PTP" is short for "peer-to-peer" file sharing. This is a way for people to directly yet discreetly exchange files. Like newsgroups, PTP is less popular than it once was, but it is still used to exchange illegal content.
*PinkCupid: This is an adult friend finder app used by lesbian women for dating and casual sexual hookups.
*Second Life: This is a popular "virtual world" that is often used for sexual gratification. Technically, Second Life is an online video game, but really it is an opportunity to create self-directed animated porn.
*Selfie: This is a digital self-snapshot, usually taken using the camera in one's smartphone. Selfies are often sexual in nature. They are very easy to post onto social media sites and to share via text messaging.
*Sexnology: Technology used to generate or enhance sexual pleasure.
*Sexting: This is the sending of sexualized texts, often with an erotic image (usually a selfie) attached. Sexting is done to flirt, to titillate, to exhibit, and sometimes even to harass and denigrate.
*Skout: This is an adult friend finder app used by straight people for casual sexual hookups.
*Skype: This is a popular video chat service, sometimes used for sexual purposes.
*Snapchat: Snapchat is a photo-based social media site. It is becoming very popular with teens and young adults. Like other social media sites, photos can sometimes be sexual.
*Teledildonics: This refers to digitally-driven devices used for sexual stimulation. In other words, sexual implements that can be synced to onscreen pornography or even the actions of another live person.
*Tinder: This is an adult friend finder app used by straight people for casual sexual hookups. Most users are young adults.
*Webcam: This is a camera that is (usually) built into a computer, tablet, smartphone, or some other digital device. Webcams feed real-time imagery into digital networks, to be viewed by a person or people hooked into that particular network.
*Video Chat: Facilitated via webcams, video chat lets people see each other while they chat, sort of like the science fiction "video phone" of yesteryear.
*Virtual Sex: This refers to sex that occurs only online. Usually it refers to webcam sex (mutual masturbation through video chat). Additionally, there are numerous "virtual sex worlds," like Second Life, in which users create avatars (digital versions of their idealized selves) and then guide those avatars through sexual activity.

Needless to say, the above list is incredibly incomplete, and there are always new terms to learn. Nevertheless, it does contain the basics in case you'd like to be conversant on your next virtual spelunking expedition. I should also state that if you do choose explore online dating and hookups, you shouldn't feel bad about asking for clarification if/when someone uses a term you're not familiar with. It's a lot better to feel a bit embarrassed about the fact that you're not totally up-to-date with the sexicon than to find yourself unwittingly agreeing to something that doesn't turn you on or that might even frighten or endanger you.