The following terms for MS-related data are used in this tutorial and the OpenMS class documentation:

• raw data point
  An unprocessed data point as measured by the instrument.
• peak
  Data point that is the result of some kind of peak detection algorithm. Peaks are often referred to as sticks or centroided data as well.

• spectrum / scan
  A mass spectrum containing raw data points (raw spectrum) or peaks (peak spectrum).

  

  Part of a raw spectrum (blue) with three peaks (red)
• map
  A collection of spectra generated by a HPLC-MS experiment. Depending on what kinds of spectra are contained, we use the terms raw map or peak map. Often a map is also referred to as an experiment.

• feature
  The signal caused by a chemical entity detected in an HPLC-MS experiment, typically a peptide.

  

  Peak map with a marked feature (red)