Meaning of MARKER in English
A ~ is an object which is used to show the position of something, or is used to help someone remember something.
He put a ~ in his book and followed her out.
If you refer to something as a ~ for a particular quality or feature, you mean that it demonstrates the existence or presence of that quality or feature.
Vitamin C is a good ~ for the presence of other vitamins and nutrients in frozen food.
N-COUNT: oft N for n
A ~ or a ~ pen is a pen with a thick tip made of felt, which is used for drawing and for colouring things.
Draw your child’s outline with a heavy black ~.
Collins COBUILD. Толковый словарь английского языка для изучающих язык Коллинз COBUILD (международная база данных языков Бирмингемского университета) . 2012