This is the 5986th most frequent Portuguese word.
by
The Portuguese language doesn't have the word "by." It's an English word meaning "near," "through the agency of," or "indicating the agent performing an action."
'Por' is used to indicate the agent performing the action in this passive sentence.
O livro foi escrito por Mario.
The book was written by Mario.
'Pela' indicates the path or means, conforming to the usage of 'by' as in proximity or travel along a location.
Ela passou pela ponte ao entardecer.
She went by the bridge at dusk.
'Até' serves the purpose of indicating the time frame before which the action occurred, comparable to 'by' regarding time limits.