Excuse me if this has been asked before, but what is the notation called when after the timing there is:
two quavers = one crotchet, one quaver, as a triplet
An example is on this music
This is swung eighths; more loosely, the music has "swing". More precisely, I'd refer to it as "triplet swung eighths" or "triplet feel" if the intent is more of a 2/3,1/3 breakdown. In blues influenced music, it might be referred to as a [blues] shuffle. In classical music it is referred to as notes inégales.
Jazz purists may balk at the term "swung" (or swing) since in that idiom, the term swing conveys a rhythmic feel that is distinct from whether the initial eighth is elongated (that's why it's indicated as being loose talk).
It is quaver triplets. Often called 'swing' time. Obviously easier to write out and read as standard quavers, the first being played twice as long as the third.