hi there

i have a question to all the great painters and every anglophone person (and those speaking better english than i do - in short terms: everyone):

i often hear you talking about marks in relation to painting.
i have a rough, undefined idea what it could be but nothing concise that i know what to practise more.
i feel that a good set of marks is what can give a painting the punch it needs. so i'm interested in knowing exactly what marks are.

every definition, example or anything else tzhat helps me understanding the idea of marks is highly appreciated.

thank you.