The word 'asana', broadly speaking, can be translated as posture or pose. In the more physical practises of yoga, we move through different 'asanas' each with their own names and meanings. Since yoga is an ancient practise, these names come from Sanskrit (the classical Indian language).
If you are new to yoga, you will probably trying to take in all the new vocabulary of the different poses and while it may be overwhelming at first, you should be able to get the basics down in no time :)
Here is a small library of a few poses to get you: