countersign

名词 countersign:

1. a secret word or phrase known only to a restricted group
   同义词：password, watchword, word, parole
2. a second confirming signature endorsing a document already signed
   同义词：countersignature

动词 countersign:

1. add one's signature to after another's to attest authenticity

coun.ter.sign

v.tr.（及物动词）
coun.ter.signed,coun.ter.sign.ing,coun.ter.signs
To sign (a previously signed document), as for authentication.
会签，确认：签（一个已签文件），如为了使之生效
n.（名词）
A second or confirming signature, as on a previously signed document.Also called countersignature
连署，副署：第二次或确定性签名，如在已签文件上也作 countersignature

A secret sign or signal to be given to a sentry in order to obtain passage; a password.
暗号：为通过岗哨而必须给出的秘密记号或口令；暗语
A secret sign or signal given in answer to another.
应答的口令：为回答中一个口令而给出的秘密记号或口令