upward bow pose
If you are not familiar with its name you can see it on the Card where it makes convenient handles for Etruscan nudists.
ūrdhva + dhanur + āsana
ūrdhva upward, erect
Literally ‘grown (tall)’ from the root vṛdh grow, increase, as is vṛddha ‘(grown) old.’ The upface of upface dog is ūrdhva-mukha.
(Similar semantics join Latin altus tall, source of altitude, which is originally ‘(fed) tall’—via the alimentary canal—and its English relative old, also originally meaning nourished: fed > grown > old.)
Derived from the name of a tree, presumably one at some point used for making bows.
āsana sitting, position, pose
The ūrdhva is added to distinguish the pose from dhanur-āsana ‘bow pose’ (which is actually the name of two completely unrelated poses).
This kind of distinguishing marks the name as modern—where a large number of poses had to be marshalled and named as a system—some old, many recent, but all by convention needing a name in Sanskrit.
Iyengar’s 1966 Light on Yoga contains 200 hundred poses. Some of these are named in runs like the Warrior poses (vīra-bhadrāsana) 1, 2, 3; or the rather confusing series of four Marīchy-āsanas. By contrast traditional Haṭha-yogic texts dealt with smaller numbers—the earliest texts only one or two or none. The 15th century Haṭha-pradīpika (the first ‘Light on Yoga’) had 15 poses until a new version of it in the 18th century was fitted out with 96 poses. An account of the accumulation of poses in texts up to the the imposition of the British Raj is given in this article by Jason Birch.