GBP/NZD is the rate at which the British pound converts into New Zealand dollars, showing how many of the latter one pound will buy. It is one of the more volatile crosses on the board, combining a major currency with a smaller, risk-sensitive one, and its swings can be large while its liquidity is thinner than the majors. Traders do not use a set nickname for it.
The pound is the base currency and the New Zealand dollar the quote currency, so a quote of 2.0800 means one pound is worth 2.0800 New Zealand dollars. A rising price means the pound is strengthening against the New Zealand dollar; a falling price means it is weakening. You trade GBP/NZD as a forex CFD, taking a position on where the price is headed rather than exchanging currency: go long if you expect the pound to gain, short if you expect it to give ground. Pips are quoted to the fourth decimal place, and your result is the pip change multiplied by your position size.
What moves GBP/NZD most is the combination of Bank of England policy and swings in global risk appetite. The pound responds to UK growth, inflation and political headlines, while the New Zealand dollar tends to rally when risk sentiment is buoyant and sell off when it sours. Those two forces can reinforce or offset each other, which is a big reason the cross moves in such wide ranges.
Say GBP/NZD is trading at 2.0800 and you expect the pound to strengthen, so you buy one standard lot (100,000 pounds). Each pip is 0.0001 and worth 10 New Zealand dollars, so a 50-pip rise to 2.0850 gives:
50 √ó 10 New Zealand dollars = 500 New Zealand dollars
A 50-pip fall to 2.0750 would instead cost 500 New Zealand dollars. Since the position runs on leverage, you fund only a small part of the contract value as margin, which makes both the upside and downside larger.