A&G camera
 Acquisition and Guiding camera - 4MOST will have two of these cameras, which are used to ensure accurate pointing of the telescope.
AESOPAustralian-European Southern Observatory Positioner - The fibre positioner unit that is being built for 4MOST. More can be read about AESOP here
AIPLeibniz-Institut für Astrophysik Potsdam - Where the Project Office is situated.
Consortium
The consortium is the group of institutes responsible for designing, building, and planning for the 4MOST instrument and survey.
DXU
Data eXchange Unit - The format for 4MOST data products. Documentation on these can be found on the 4MOST website.
DMS
Data Management System - The 4MOST system that will reduce, analyse, validate, and publish all data.
eROSITA
extended ROentgen Survey with an Imaging Telescope Array - An X-ray imaging instrument to be launched in 2019, which will perform an all-sky survey.
ESA
European Space Agency
ESO
European Southern Observatory - the organisation which owns and operates the VISTA telescope
EUCLID
An optical/near-infrared space telescope to be launched by ESA in 2021.
Fibre-hour
One hour of observing with one fibre.
Field-of-View (FoV)
The size of the area on-sky that 4MOST can observe with one pointing.
Figure-of-Merit (FoM) 
A method of quantifying how much progress a 4MOST survey has made towards meeting its goals during operations.
Gaia
An ongoing ESA space mission designed to measure astrometry and photometry of more than one billion stars in the Milky Way. Gaia data will form the basis of the 4MOST Galactic surveys input catalogues.
GTO
Guaranteed Time Observations - In exchange for building 4MOST, the Consortium receives 70% of the time available on VISTA over the course of the five years.
HRS
High Resolution Spectrograph - 4MOST has one high-resolution spectrograph, with a resolving power of R > 18,000.
L0, L1, L2
Different types of data products:
  • L0 are the raw images from the telescope
  • L1 are the reduced spectra
  • L2 are the advanced products from the scientific pipelines (e.g. stellar parameters, redshifts, selection functions).
LoI 
Letters of Intent The community can propose a survey for 4MOST, in order to do this they must fist submit a letter of intent. ESO will issue a call for these letters of intent in summer 2019.
LRS
Low Resolution Spectrograph - 4MOST has two high-resolution spectrographs, both with a resolving power of 4,000 < R < 7,800.
LSST
Large Synoptic Survey Telescope - an 8.4m telescope currently under construction, with full operations scheduled for 2022. LSST will image the entire available sky every few nights for 10 years, in order to provide time-domain science.