This is the 8649th most frequent Polish word.
płocka
"Płocka" refers to something related to the city of Płock in Poland, such as a street name or descriptor.
Here, 'płocka' refers to the city of Płock in Poland, in a declined form used with preposition 'do', indicating direction.
Wybiorę się na wycieczkę do płocka.
I will go on a trip to Płock.
In this sentence, 'płocka' is used adjectivally to describe a district that is part of or related to Płock.
Mieszkam w płocka dzielnicy.
I live in Płock's district.
Here, 'płocka' functions as an adjective describing the scientific conference, associating it with the city of Płock.