一审（first instance）是指法院对案件的最初一级审判。一审的程序可以分为普通程序和简易程序两种。

在中国，普通的第一审案件由基层人民法院管辖，但是性质较严重、问题较复杂、影响较广大的第一审案件，按其不同程度，分别由中级人民法院、高级人民法院、最高人民法院管辖。最高人民法院的第一审就是终审。

二审（second instance）又称上诉审程序，是第二审人民法院根据上诉人的上诉，就第一审人民法院尚未发生法律效力的判决或裁定认定的事实和适用法律进行审理时，所应当遵循的步骤和方式方法。

再审（retrial/to hear a case again），是指法院对已经发生法律效力的判决、裁定，在具有法律规定的再审事由时，依据法律规定的程序对原审案件也称“本案”再次进行审理并作出裁判的一种特别救济程序。再审程序包含一整套启动、审查再审事由、原审案件再次审理的法定程序。

重审（remit/remand a lawsuit for a new trial），是上级法院认定审理不当要求重新审理，撤销原来的审理结果，发回重新审理。

重审与再审的区别：

重审是上级法院认定审理不当要求重新审理，撤销原来的审理结果，发回重新审理。

再审是为纠正已经发生法律效力的错误判决、裁定、依照审判监督程序，对案件重新进行的审理。

相关双语法规：

《民诉法》第四十条：

人民法院审理第一审民事案件，由审判员、陪审员共同组成合议庭或者由审判员组成合议庭。合议庭的成员人数，必须是单数。

Civil cases of first instance shall be tried in a people’s court by a collegial bench consisting of both judges and assessors or of judges alone. The numbers of members of a collegial bench shall be odd.

适用简易程序审理的民事案件，由审判员一人独任审理。

Civil cases to which summary procedure is applied shall be tried by a single judge alone.

陪审员在执行陪审职务时，与审判员有同等的权利义务。

When carrying out their duties as assessors, the assessors shall have equal rights and obligations as the judges.

《民诉法》第四十一条：

人民法院审理第二审民事案件，由审判员组成合议庭。合议庭的成员人数，必须是单数。

Civil cases of second instance shall be tried in a people’s court by a collegial bench of judges. The numbers of members of a collegial bench shall be odd.

发回重审的案件，原审人民法院应当按照第一审程序另行组成合议庭。

For the retrial of a remanded case, the people’s court of first instance shall form a new collegial bench according to the procedure of first instance.

审理再审案件，原来是第一审的，按照第一审程序另行组成合议庭；原来是第二审的或者是上级人民法院提审的，按照第二审程序另行组成合议庭。

If a case for retrial was originally tried at first instance, a new collegial bench shall be formed according to the procedure of first instance; if the case was originally tried at second instance or was removed to a people’s court at a higher level for trial, a new collegial bench shall be formed according to the procedure of second instance.

参考双语例句：

At its sixty-second session, the General Assembly decided to establish: (a) a two-tier formal system of administration of justice, comprising a first instance United Nations Dispute Tribunal and an appellate instance United Nations Appeals Tribunal; (b) the Office of Administration of Justice, comprising the Office of the Executive Director and the Office of Staff Legal Assistance and the Registries for the United Nations Dispute Tribunal and the United Nations Appeals Tribunal; (c) a single integrated and decentralized Office of the Ombudsman for the United Nations Secretariat, funds and programmes with branches in several duty stations and a new mediation division; (d) the Internal Justice Council; and (e) the Management Evaluation Unit in the Office of the Under-Secretary-General for Management (resolution 62/228).

大会第六十二届会议决定：(a) 设立一个两级正式内部司法系统，第一级是一审联合国争议法庭，第二级是上诉审联合国上诉法庭；(b) 设立内部司法办公室，由执行主任办公室、工作人员法律协助办公室以及联合国争议法庭书记官处和联合国上诉法庭书记官处组成；(c) 为联合国秘书处、各基金和方案统一建立一个统筹一体、分散作业的监察员办公室，在几个工作地点都有分支机构，并设立一个新的调解司；(d) 成立一个内部司法理事会；(e) 在主管管理事务副秘书长办公室设立一个管理评价股(第 62/228 号决议)。

Under the statute and the Rules of Procedure and Evidence, the absentee retains, however, some fundamental rights: (a) he or she may appoint defence counsel of his or her choosing; (b) he or she may terminate his or her absence and appear in court (rule 108); (c) if he or she has not appointed counsel of his or her choosing, once the trial is over, he or she may ask for a retrial (rule 109); (d) if he or she has appointed defence counsel of his or her choosing, he or she has the right to appeal against the judgement of the Trial Chamber.

但是，根据《规约》及《程序和证据规则》，缺席人仍有一些基本权利：(a) 可以指定自己选择的辩护律师；(b) 可以终止缺席而出庭(规则108)；(c) 如果没有指定自己选择的辩护律师，审判结束后，可以要求重审(规则109)；(d) 如果指定了自己选择的辩护律师，则有权对审判分庭的判决提出上诉。