What is armstand?

Some articles on armstand:

Diving At The 2000 Summer Olympics – Women's 10 Metre Platform
... dive, a back dive, a reverse dive, an inward dive, a twisting dive and an armstand dive ... an inward dive, a twisting dive and an armstand dive, all limited in difficulty degree ... a reverse dive, an inward dive, a twisting dive and an armstand dive ...
Competitive Diving - Dive Groups - Dive Numbers
... For Group 6 – Armstand – the dive number has either three or four digits Three digits for dives without twist and four for dives with twists ... In non-twisting armstand dives, the second digit indicates the direction of rotation (0 = no rotation, 1 = forward, 2 = backward, 3 = reverse, 4 = inward) and ... Inward-rotating armstand dives have never been performed, and are generally regarded as physically impossible ...
Diving At The 2000 Summer Olympics – Men's 10 Metre Platform
... a reverse dive, an inward dive, a twisting dive and an armstand dive ... of a front dive, a back dive, a reverse dive, an inward dive, a twisting dive and an armstand dive ... dive, an inward dive, a twisting dive and an armstand dive, all limited in difficulty degree ...