倡议书在英语中叫做"proposal"。它是指一个人或组织提出的解决问题或改变现状的方案。例如：

"We are pleased to present our proposal for the new office building project."

"Our proposal outlines the steps we will take to reduce plastic waste in our community."

"After careful consideration, we have decided to accept the proposal from the marketing firm."

来源：倡议书一词来源于拉丁语propositio，意思是"提出的主张"或"提出的方案"。