This is the 15995th most frequent Polish word.
trolejbusy
Trolejbusy: Trolleybuses.
Here, 'trolejbusy' is used as the subject of the sentence to indicate a mode of transportation.
Trolejbusy są ekologiczną alternatywą dla tradycyjnych autobusów.
Trolleybuses are an ecological alternative to traditional buses.
In this sentence, 'trolejbusy' is used in the accusative plural form to refer to the objects of the action.
Wczoraj widziałem nowoczesne trolejbusy w centrum miasta.
Yesterday, I saw modern trolleybuses in the city center.
Here, 'trolejbusami' is in the instrumental plural form, indicating the means or cause related to the issue described.