This is the 2165th most frequent Chinese word.
打开
"打开" means "to open."
Here, "打开" is used in a literal sense to mean opening a physical item, such as a window.
请你打开窗户让空气流通一下。
Please open the window to let the air circulate.
In this context, "打开" is used to mean turning on an electronic device.
他打开了电脑并开始工作。
He turned on the computer and started working.
Here, "打开" is used metaphorically to mean expanding or broadening one's scope or understanding.