ONDE and AONDE - What's the difference?
Fernando Nonohay Nonohay 
In this post, you'll learn the exact difference between them so that you will always know when to use "onde" and "aonde".
A lot of people confuse onde and aonde - including Brazilians!
If you've been studying Portuguese for a while you should know that onde means where:
Onde você mora?
Where do you live?
O escritório onde eu trabalho é muito pequeno.
The office where I work is very small.
Aonde should be used when movement to a place is involved, therefore it's often used with verbs that denote movement, such as ir (to go), chegar (to arrive), levar (to take something somewhere - also see post Verbs TRAZER and LEVAR).
The a before aonde is a preposition that means to,as we've seen in another post: Portuguese Prepositions with Verbs of Movement
Aonde você foi ontem?
Where did you go yesterday?
Aonde você quer chegar com tanta pressa?
Lit.: Where do you want to get to in such a hurry?
In colloquial conversation it's relatively common for Brazilians to use onde and aonde interchangeably - however, it's often frowned upon. I personally think you shouldn't use them interchangeably - it's really not that difficult to know when to use one or the other, so I would recommend that you do try and use them correctly.
However, it's not the end of the world you mix them up, it's not something that will have a major impact on you being understood.
Categories: : Vocabulary