This is the 2844th most frequent Portuguese word.
c
"C" in Portuguese is the third letter of the alphabet.
Here, 'c' again functions as a shorthand for 'com', meaning 'with'. It indicates the object (the glass) which might be knocked down.
Cuidado para não derrubar c copo.
Be careful not to knock down the glass.
Once more, 'c' is a short form of 'com'. In casual speech, 'c' simplifies expressing possession or accompaniment, implying that the cellphone is currently in the person's hand.
Ele está c celular na mão.
He is holding a cellphone in his hand.
In this sentence, 'c' is a contracted form of 'com', meaning 'with'. It is used to describe the shirt as having long sleeves, reflecting a specification concerning its characteristics.