Dog with the Spanish tag (5)
I believe the answer is:
label
'tag' is the definition.
(I know that tag is a more specific form of be known as)
'dog with the spanish' is the wordplay.
'dog' becomes 'lab' (short for labrador).
'with' is a charade indicator (letters next to each other).
'the spanish' becomes 'el' ('the' in Spanish).
'lab'+'el'='LABEL'
(Other definitions for label that I've seen before include "Identity tag" , "Tag; record company" , "Classifying name" , "Put a name to" , "Identify" .)