This is the 8270th most frequent Polish word.
plk
"Pułk" in Polish means "regiment" in English.
In this sentence, 'pułkownik' denotes the military rank, often abbreviated as 'płk' in written form.
Pan pułkownik poprowadziję szkolenie dla żołnierzy.
Colonel will lead the training for soldiers.
Here, 'płk' is an abbreviation representing 'półk', meaning 'bank or shore', usually part of geographic descriptions.
Oddział doszledł aż po płk rzeki, gdzie założył obóz.
The unit reached as far as the bank of the river, where they set up camp.
In this usage, 'płk' is part of an idiomatic context referring to a specific junction, 'point', within thematic discussions.