"笔直"在英语中可以翻译为"straight".

"Straight"来源于古英语"streht", 源于古德语"straht", 意思是"细长的"或"直的".

下面是几个例句：

The flagpole is straight. (那根旗杆是笔直的。)
She has straight hair. (她的头发是笔直的。)
He stood up straight. (他站直了起来。)
The road ahead is straight. (前面的道路是笔直的。)