You may have come across a lot of words in the English language that have meanings so similar that it becomes extremely difficult to differentiate between them and learn their proper usage.
Words such as donde and adonde, however, make it quite obvious that the Spanish language is no different from the English language as far as the difficulty in distinguishing between certain words and learning their proper usage is concerned.
Looking for the definitions of the aforementioned Spanish words in an English language dictionary will be of no use, as they are unlikely to be defined in there. The confusion pertaining to the difference between donde and adonde is such that even Spanish speakers often struggle to use the appropriate word.
However, despite all the confusion surrounding the definition and usage of donde and adonde, the two words can still be distinguished, thus making it possible to learn their correct use.
While both the words are used in the Spanish language to indicate the concept of “where,” donde functions as a relative pronoun that is used in a slightly broader sense than adonde, which typically functions as a relative adverb.
Donde only inquires about 'where' in a general sense, whereas its counterpart inquires about 'where' in detail, such as the direction or even the destination.
If someone is only interested in knowing 'where', as in “where is my sister?” the appropriate word to use in such a scenario would be donde, for example, “Donde esta mi hermana?”
However, if someone is interested in knowing exactly where someone is heading, then the most appropriate word to use in such a scenario would be adonde, for example, “Adonde vas?”
Another thing to keep in mind is that when you have direction in mind, the word adonde is the one that you should be using while asking the question, whereas when you are not interested in the direction, donde is the most suitable word.
One more difference between donde and adonde lies in the types of words that come before or after them. The former is typically followed by a noun or a proposition, whereas the latter is normally used before a verb of motion.