This is the 4761st most frequent Russian word.
замечать
"Замечать" means "to notice" or "to observe."
Here, 'заметил' is used in its basic sense which means 'to notice' or 'to observe something unintentionally.
Я заметил странное движение в кустах.
I noticed strange movement in the bushes.
In this sentence, 'заметила' is used to imply 'realizing or observing a change or detail' in a situation.
Ты заметила, что он больше не звонит?
Did you notice that he no longer calls?
Here, 'замечать' is in the form indicating 'actively bringing attention to something important' as part of communication or observation efforts.