Shortening of the word Gathering.
Its like a party but smaller, usually with alcohol, and on the occasion drugs.
"Hey man you going to that gatho tonight?"
by Addie__xx March 1, 2008
Young peopel use the word Gatho instead of party to sway parents to let them go. It is meant to convey a smaller and more innocent night with friends, but in reality is just another word for party. They also dont realise how douchey they sound when they say gatho, and also how much it makes me want to punch them right in the face.
e.g Sarah: Mum can I go to Sam's party tonight?

Mum: Party! No way, you will be doing drugs and having sex, absolutely not.
e.g Sarah: Mum, Sam is having a gatho with a couple of friends can i please go.

Mum: ohh, a gathering that sounds nicem have a good night.
A Gatho is short for "a gathering" of friends for the purpose of having a good time. Usually for the consumption of alcohol.
Cello's having a Gatho down south, do you wanna go?
by MidnightOutlaw December 30, 2016
A style of kissing at a Gatho involving excessive dry humping of your partners leg whilst making noisy slurping kissing sound whilst clashing your teeth together.

To be considered Gatho humping it must be carried out in the vicinity of the other Gatho goers and making said goers feel extremely uncomfortable.
Did you see those two freaks Gatho Humping last night?

I really enjoyed Gatho Humping you last night.

Man I was so wasted last night I hope I didn't engage in any Gatho Humping.
by LTLFTC September 24, 2017
Gatho Humping, is violent face sucking, with the intention to create one giant hickey on a victim or partners face, whilst vigorously grinding on a partner. Gatho Humping must be preformed in front of a crowd to make them feel un comftorable and awkward.
Man I really enjoyed Gatho Humping you last night.

I had such a blast Gatho Humping Joe Blogs last night.

Eww did you see those two weirdos Gatho Humping on the ground *puke*
by pedro Clarlstin September 24, 2017