The Sanskrit word Padma means the lotus. Hence, its English translation is Lotus Posture. The posture is called as such because it resembles the Lotus flower. Kamalasana is the alternative name in Sanskrit.
Asana in Yoga is also known as Yogasana, Yoga Pose, or Yoga Posture. In Raja Yoga, Asana means a sitting posture. Of course, a sitting posture meant for meditation. But in Hatha Yoga, Asana is more than that. It extends to mean other postures also like back bending, forward bending, and inverted postures.