This is the 8619th most frequent Polish word.
próbna
"Próbna" in English means "trial" or "test."
Here, 'próbna' is used to describe 'wersję' (version) as 'trial', indicating it is not the final product but instead is for testing.
Otrzymałem próbna wersję oprogramowania.
I received a trial version of the software.
In this sentence, 'próbna' modifies 'lekcje' (lesson), implying the lesson serves as a test or preview.
Mamy próbna lekcje tańca w sobotę.
We have a trial dance lesson on Saturday.
'Próbna' here qualifies 'minutę ciszy' (minute of silence), suggesting the context is preliminary or experimental.