Spanish article about silver English coin once (5)
I believe the answer is:
eagle
'coin once' is the definition.
(historic US coin)
'spanish article about silver english' is the wordplay.
'spanish article' becomes 'el'.
'about' is an insertion indicator.
'silver' becomes 'ag' ('Ag' can be a synonym of 'silver').
'english' becomes 'e' (abbreviation).
'el' placed around 'ag' is 'eagl'.
'eagl'+'e'='EAGLE'
(Other definitions for eagle that I've seen before include "five buck bit, or more" , "It normally takes two or three shots to shoot this" , "Bird with hooked bill and long broad wings" , "Former US coin" , "Keen-eyed bird" .)