Learn Danish: Hvor er taxaen? - Where is the taxi?

In Danish, the word for 'the' is usually added to the end of the noun instead of being a separate word. The base word is taxa (taxi). By adding the ending -en, it becomes taxaen (the taxi).

Since taxa gets an -en ending, does that mean it is an 'en' word?

Yes! Taxa is a common gender word, so we say en taxa for 'a taxi'. That is why it takes the -en suffix to mean 'the taxi'. If it were a neuter gender word, it would take an -et ending instead.

We are learning about direction words like til (to) and fra (from). Why aren't they used here?

This sentence asks about a stationary location ('Where is it located right now?'), so we just use hvor (where) and the verb er (is). If you wanted to ask about movement or direction, like 'Where is the taxi going to?', you would need direction words, but for a simple location, hvor is all you need.