penwidth 5 sets the width (the size) of the pen to 5 pixels. From now on every line the turtle draw will have a thickness of 5, until we change the penwidth to something else.
ancholapis 5 fai que o ancho (o tamaño) do trazo sexa de 5 píxeles. De agora en diante cada liña que debuxe o sapoconcho terá un gordo de 5, até que modifique o ancholapis.