This is the 11873rd most frequent Russian word.
запланированном
"Scheduled" or "planned."
Here, 'запланированном' (planned) is used as an adjective describing the location where the meeting was scheduled to occur.
В запланированном месте встречи никого не оказалось.
At the planned meeting location, no one was present.
'Запланированном' is being used to modify 'мероприятии' (event), indicating it was prearranged.
Мы обсуждали детали о запланированном мероприятии.
We discussed the details of the planned event.
In this case, 'запланированном' describes the prearranged or scheduled visit.