Lumira Discovery : Count a "String" in a Dataset

Hi there :)

i have a "Newbie Question", i hope somebody can help me

I have a dimension in the Lumira, a table below it - here I would have to count a certain word in it to then get the sum of it as a result.

I can count things via Measures, but how do I count a specific word? What function can I use for this? Unfortunately, I can't find anything in the function table :-/

Thank you in advance!