Article on travel in the past (3)
I believe the answer is:
ago
'in the past' is the definition.
(synonyms)
'article on travel' is the wordplay.
'article' becomes 'a' (the indefinite article in English).
'on' says to put letters next to each other.
'travel' becomes 'go' (synonyms).
'a'+'go'='AGO'
(Other definitions for ago that I've seen before include "Gone, past, since" , "Back (in time)" , "Previously" , "Earlier, gone by" , "Time past" .)