look up any word, like trill:
 
8.
A drug that can be really great, or really horrifying. Even experienced users can have a mind-frying bad trip that requires some time in a mental institution, and there is no rhyme or reason as to why this happens. Acid-heads like to brag about how many times they've taken the drug, but most of the time they are lying.
DooOO000d, me an a friend dropped acid last night and we got stopped by the pigs and got questioned for 10,000 years.
by The Dodger August 12, 2004
 
9.
Acid is
a) the really strong drug, known as LSD
b) the stuff that burns your face off if you somehow manage to get it there during chemistry class.
"I got some acid yesterday and I'm still trippin"

or

"God, I can't feel my face because i got acid on it last class period!!"
by Jesse March 06, 2005
 
10.
A powerful psychoactive drug that breaks down subconcious barriers and will make your mind race through the corridors of human perception. While under the influence you'll often hear people say "Dude Im trippin so hard" many many times as a way to come to terms with the phenomena that is occuring. Visual filters in the brain are broken down to let raw, unfiltered data in. It is usually hard to talk and move while your under the influence, so a suggestion would be to find a comfy chair, put some Phish on, and perceive.
Scott: "Dude Im trippin on acid"

Matt: "Stop trying to put a word like "trippin" to the experience your having, just flow with it man, if you fight the ocean you will drown!!!!"
by Kevin Rollengardner January 13, 2007
 
11.
A style of techno/house music, noted for its prominent use of the of the Roland TB-303, a synthesizer with a distinctive (and very funky) sound. Variants include hard acid, acid house, acid trance, etc. Not all music that includes a 303 is necessarily acid, and not all acid music makes use of the 303 (but most of it does).

Some suggest that the word is derived from the phrase "acid burn" - a slang term from the early days of house music, referring to the practice of sampling from another musician's records (see bite).

Others cite a 1985 house single by Phuture called "Acid Trax", which is recognized as one of the first house records to make use of the 303.

A more concrete theory is that it refers to the drug LSD, which is commonly used at raves where acid house is played. Given the psychedelic nature of acid house, this interpretation is certainly part of the popular understanding of the term, if not necessarily its historic origins.
Drum & bass is okay, but what I really want to hear is some nice tweaky acid.
by Greenie December 10, 2003
 
12.
LSD or acid (lysergic acid diethylamide) is the most commonly used hallucinogen (also known as psychedlics). It is considered a typical hallucinogen causing similar effects to other hallucinogens like mescaline, psilocybin (mushrooms), and ibogaine. LSD became popular in the counterculture of the 1960s and 1970s, but since then its use has been limited to people in the Rave or club scenes. According to the College Alcohol study, only 9.4% of Brown students have ever used LSD.

LSD is usually taken by ingesting small tabs of paper (frequently placed under the tongue) which have been soaked in the liquid form of the drug then dried. In rare cases it is taken in a liquid, gelatin, or tablet form. Sometimes a dose is soaked into a sugarcube. Doses range from 20 to 100 micrograms now, though in the 1960s they ranged from 100 to 200 micrograms. Because LSD is produced illegally, it is difficult to know how strong a dose is. The effects of the drug begin in about 30 minutes and last up to 12 hours. It can be very difficult to sleep if LSD has been taken in the last 6 hours.
acid is a very powerful drug,
but it is not as damaging as many people like to portray it.
by tjbcreations February 07, 2008
 
13.
LSD was first synthesized in 1938 by Swiss chemist Dr. Albert Hofmann at the Sandoz Laboratories in Basel, Switzerland, as part of a large research program searching for medically useful ergot alkaloid derivatives. Its psychedelic properties were unknown until 5 years later, when Hofmann, acting on what he has called a "peculiar presentiment," returned to work on the chemical. He attributed the discovery of the compound's psychoactive effects to the accidental absorption of a tiny amount through his skin on April 16, which led to him testing a larger amount on himself for psychoactivity.

sadly the acid that is taken today compaired to 20 years ago is a basterdised version with more effects to physical sensation and a reduction in auditory and visual stimulation. it is said to be a hallucinogen but in it has been proven scientificaly that it actualy causes a temporay break down in a mental berior wich causes you to notice signals that you would normaly not notice it also sticks a door stop in the door to your subconcious wich allows your emagination to run wild there by the hullucination is based on an actual event taking place.
guy1 "dude i took a bad hit of acid last night and i had no clue what was going on."

guy2 "you meen you took real acid last night not that stupid wuss bag shit u normaly took and had the best trip of your life u fuckin tard."
by luke neville November 17, 2006
 
14.
slang for LSD, an extremly powerful drug, that makes you see some crazy shit...depending on the enviorment a good trip could be the best thing ever or a bad trip could put you in the booby hatch
Well I been trippin' for 10 hours on 3 hits of liquid microdot (I'm on acid - acid)
Gettin' chased around the car by some midgets in the parking lot (I'm on acid - acid)
Feedin' doritos to a tree, a million spiders after me (I'm on acid - acid)
I'm runnin' around havin' a fit, on myself I'm about ta shit (I'm on acid - acid)
by jizzle dizzle November 05, 2006