Not sure what a certain term you've heard means? Here's a basic list of different terms in hang-gliding and their meaning:

ASL: Above Sea level

Basetube: Part of the control frame

Boo Wah: Brilliant flying conditions

Cloud Suck: This is where pilots get 'sucked' into clouds as the lift gets bigger nearer the clouds.

Control Frame: The frame the pilot uses to control the glider

Downtube: Part of the control Frame

FPM: Feet Per Minute

GPS: Global Positioning system

H1 - H5: These are ratings to show how experienced pilots are. H1 is the least, H5 the most.

LZ: Landing Zone

MSL: Mean sea level

s2f: This stands for speed to fly which is the optimum speed for flying depending on what the conditions are

VG: Varible Geometery

Wuffo: A person who is not a pilot; and asks 'what for' questions.