verb · to lay a foundation, either literally in construction or figuratively for a project or career

良好的教育为他的人生打底。

verb · to eat something before drinking alcohol to protect the stomach and slow intoxication

喝酒前先吃个馒头打底，不容易醉。

verb · to make a first sketch or apply a base coat of paint, primer, or makeup

画家先用铅笔在画布上打底，然后再开始上色。