Archers can shoot any number of arrows over any distances at any targets.
That makes comparing your results over time or to other archers somewhat difficult. You may score 420 one day but only 324 the next. But if the first day you shot 10 ends at a 122 cm target from 15 metres and the second 6 ends at an 80 cm target face from 30 metres away you have actually improved quite significantly.
"Rounds" simplify comparisons. They are names given to specific combinations of arrows, distances and faces. e.g. a "WAA 600" is 90 arrows at a 122 cm target from 30 metres.
People have been defining rounds for hundreds of years. The "York" for example—72 arrows from 91 metres, 48 arrows from 73 metres and 24 arrows from 55 metres, all at a 122 cm face—was first shot in York, England in 1844. [Those distances may seem odd but remember that round pre-dates the metric system: they equate to 100, 80 and 60 yards respectively.]
When rounds prove particularly popular, variants are often defined for the benefit of more or less able archers. The "720"—72 arrows from 70 metres at a 122 cm face—is currently the most common round shot in national and international competitions. Consequently there are rounds such as the "720 (20m)", "720 (35m)", and "720 (45m)". Rounds with similar attributes can be considered as falling within "families".
Because there are so many rounds—you can imagine the number of possibilities—various archery bodies recognise various sub-sets. The fifty-odd rounds detailed below are those you are likely to encounter in New Zealand.