Normally FIM means remove 85 to 90% of the growth tip.

OK, here's some I can remember. I'm going way back on some, but all are still legitimate.

PPM - Parts Per Million
EC - Electrical Conductivity
TDS - Total Dissolved Solids ?? How much stuff is in your water.
RO - Reverse Osmosis ?? Strips water of chemicals and contaminants.
FFT - Fog Feed Technique. Just a little ol' thing I like to call... The future!
CHAOS - Cataclysmic Horrific Annihilation Of Species (this is a real one).
KB - Killer Bud.
KGB - Killer Green Bud.
OG ?? OverGrow.com - Slang definition referring to a massive, popular weed site that got shut down.
OG - Organic Gardening ?? Actual definition. However, assume people around here are referring to the slang definition.
RZ ?? Root Zone.
SC ?? SuperCrop ?? Repeatedly smashing the stem (gently of course), with hopes that the injured part will grow back bigger, thus making nutrients able to flow more freely.
LED ?? Light Emitting Diode. No really, I??m not kidding. They??re not coming soon, they are here. Just another little ol' thing I like to call... The future! uh, of grow lights that is.
nm ?? NanoMeters ?? This is a unit of measurement for the wavelength, or color of LED light output. 430 and 675 are the two ideal numbers (if there were such a thing) for veg and bloom respectively. Our visible range is from a little under 400 to a little over 700.
mcd - MilliCanDela - The unit of measurement most commonly used to describe the intensity of LED light. It measures light production at the source of the light. Compare this number when shopping for LEDs.
OZ ?? Ounce.
O ?? Ounce ?? More for sellers and stealth.
g ?? gram.
QP - Quarter Pound.
MJ ?? MariJuana, pot, herb, dankness, weed, chronic, one-eyed trouser snake ?? No wait, not that.
CB ?? CannaBinoid - There??s a little fewer than 500 chemicals in MJ, and 69 or so are cannabinoids. They are unique to the weed plant. Guess how to remember that 2nd number. Most are abbreviated with ??CB? at the beginning, and are spelled like cannabsomething. They are responsible for the psychotropic effects (changes in your mood and consciousness), and other effects. Much is unknown, but they all work together kind of like a really smart ant farm. Some CBs do nothing but regulate others. Others grab onto your brain and some even get sucked inside. There have really not been any decent studies on all but just a few of the major ones. (PLEASE POST LINKS IF ANYONE KNOWS OTHERWISE.) The 3 CBs we are most interested in are THC, CBD and CBN.
THC ?? By far, the main cannabinoid we??re concerned with is delta-9-TetraHydroCannabinol. Hemp can contain less than 0.5%, while a prime variety like AK-47 can have as much as 22% or more. 12 is the average for THC percentage in plants siezed by law enforcement.
CRI ?? Color Rendering Index ?? This is a scale from 0 to 100 which measures how well a light can reproduce colors of things it lights up. The sun is 100, and many of both CFL and HID light manufacturers are saying their lights are 90 or above. Compare CRI before buying cheap bulbs.
K ?? Kelvin ?? A temperature scale for measuring color of light. Yes you heard right. The color of light we want corresponds to peak chlorophyll activity of plants, therefore the most efficient colors for veg and bloom lights are 5500 or 6000 (not between) for vegetative growth, preferably 5500, and 2200 or 2700 (not between) for blooming, preferably 2200. Whether you??re buying CFL or HID make sure you look for those numbers.
PH - Potential of Hydrogen (P is a logarithm). It??s one of the the most important considerations in weed farming, especially with hydroponics. Last, but the opposite of least, this measurement defines how acidic or alkaline a solution is. The lower the value, the more acidic the solution is, and the higher the value the more alkaline. Neutral is 7 and the scale is from 0 to 14. Hydroponic solutions should be around 5.5, while the soil of conventional grows should be around 6.8. The scale is logarithmic; 4 is 10 times more acidic than 5. You must buy a $25 PH meter if you plan to seriously grow anything.

Search this crap if you don??t get it. It??s need to know.

Perhaps more coming if I think of them. I'm going to have some cereal and go to bed.