This is the 989th most frequent Czech word.
vlak
Train.
In this sentence, 'vlak' is used as a noun representing a means of transport – a train.
Vlak přijel na stanici o pět minut později.
The train arrived at the station five minutes late.
Here, 'vlak' metaphorically describes a sequence – a train of thoughts.
Musíte sledovat vlak jejich myšlenek, abyste pochopili.
You need to follow the train of their thoughts to understand.
In this example, 'vlak' refers to a toy representation of a train, showing variation in usage.