From Project: Redcap
General spells, often abbreviated as "Gen", are those that may be learned in any Spell Level. The higher the level, the more difficult it is to learn, but the more impressive the effects as well.
Different levels of the same General spell are considered different spells and must be learned or developed separately, even if the level initially learned is higher than that of the second version.
The RAW (Rules As Written)
Page 115 of the Fifth Edition of Ars Magica describes General spells.