sheet an·chor
noun/ˈʃiːt æŋkə(r)/
/ˈʃiːt æŋkər/
- a person or thing that you can depend on in a difficult situation
（困难时的）靠山，指望，对策 Word Originlate 15th cent.: perhaps related to obsolete shot, denoting two cables spliced together, later influenced by sheet sense 6.