"a farewell, a bidding farewell," 1610s, from past participle stem of Latin valedicere "bid farewell, take leave," from vale "farewell!," second person singular imperative of valere "be well, be strong" (see valiant) + dicere "to say" (see diction).
中文解释
1、vale- "be well" + dict- "say" + -ion.2、字面含义：say something about be well. 其构词原理和farewell相近。3、当然，在告别的时候就会说：be well. 咱们汉语里不是就有类似的话吗：保重，一路顺风，旅途愉快。
实用例句
1. He gave a touching valediction at graduation.
他在毕业典礼上发表了动人的告别辞.
来自《简明英汉词典》
2. She will give a touching valediction at graduation.