"Danda" means "stick" in Sanskrit.
"Hala" means "Plough" in Sanskrit. This posture is called 'Halasana' because in the final position the body resembles the Indian plough.
"Janu" means "knee" and "Siras" means "head" in Sanskrit. The head is made to rest on the knee in this posture, hence the name.
"Padma" means "lotus" in Sanskrit. "Padmasana" means sitting in the "Lotus Pose". This posture is called Padmasana because the arrangement of the hands and feet resemble a lotus when seen from a distance. The two feet placed upon the opposite thigh resemble the leaves while the two hands placed one over the other resembles the lotus in full bloom.
"Paschima" means 'behind', 'back' or 'posterior' and 'Uttana' means to stretch out in Sanskrit. "Paschimotana" means stretching the posterior regions of the body.
"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.