Regularly visited Bangkok in the past (3)

I believe the answer is:
ago
'in the past' is the definition.
(three years ago means three years in the past)
'regularly visited bangkok' is the wordplay.
'regularly visited' indicates alternate letters (letters are taken at regular intervals).
The alternate letters of 'bangkok' are 'AGO'.
(Other definitions for ago that I've seen before include "Back (in time)" , "Previously" , "(Years) before the present time" , "Gone, past, since" , "In past times" .)