"Ardha" means "half" in Sanskrit. Since the full posture is difficult to be practiced, the half-posture, which is easier, is followed widely. This posture was first promoted by the great Yogi Matsyendranath, one of the founders of Hatha Yoga, and hence the name.
"Chakra" means "wheel" in Sanskrit. In the final position of this asana, the body is arched backward and resembles the rim of a wheel. Hence the name.
"Danda" means "stick" in Sanskrit.
"Shalabha" means "locust" in Sanskrit. The final position of this asana resembles a locust when it lowers its head to eat and raises its tail. Hence, the name.
"Sirsha" means "head" in Sanskrit. It is required to "stand on his head" in this asana and hence the name.
"Sukha" means "pleasant" or "comfortable" in Sanskrit. Any cross-legged sitting position which you find comfortable, in which the body does not shake and in which you can remain at ease for a long time, is called Sukhasana.
"Tri" means "three", "Kona" means "angle", and "Trikona" means "triangle" in Sanskrit The straight legs with the floor between the feet resemble the three sides of a triangle in this asana. Hence the name.
This pose is also called Downward Dog or Downward-Facing Dog.
"Ut" means 'raised' and "kata' means "hips" in Sanskrit. This posture is known as "Utkatasana" because while practicing it, the heels and hips are raised.
"Vriksha" means "tree" in Sanskrit. In the final position of this asana, you have to stand still like a tree.