Senses
垫底/ 墊底 to put on the bottom
To place something underneath as a lining, mat, or base; to put something on the bottom.
垫底/ 墊底 to tide over
To eat a small amount of food to stave off hunger before a meal or to protect the stomach before drinking alcohol.
垫底/ 墊底 to provide a foundation
(metaphorical) To serve as a basis or foundation; to provide a guarantee or reassurance that settles one's mind.
垫底/ 墊底 to come in last
(metaphorical) To be at the very bottom of a ranking or to come in last in a competition or exam.