unity of possession有两种含义：（1）占有混同，当地役权人或类似权利人取得对供役地的占有时，即为占有混同。现在，占有混同仅用来指占有是临时性的情况，如供役地所有人租用需役地，那么在租约期内地役权便会因占有的混同而消失；或者如当出租人将承租人逐出租约地时，租赁关系便会因出租人的占有混同而终止。

在古代法律文献中，占有混同含义更广，也包括另一种占有混同（unity of seisin）。另外当某人同时享有两种相关地产权时，也会发生占有混同，如承租人后来又购得租约地，就会发生占有混同、租赁关系消失的情况；（2）共同占有，指共同保有人（joint tenants）对于土地的不可分割的占有。

为了更好的理解该词，以下是该词的英文释义：Unity of possession means that each cotenant is entitled to possession of the whole property and every part thereof, subject to the same right in the other cotenants. Unity of possession is the essential dynamic present in all tenancies in common.

此外，除了unity of possession可指占有混同外，还有unity of seisin可指占有混同，其指地役权人或类似权利人取得对供役地的占有（seisin）的情况，通常是对两块土地均享有非限嗣继承的占有权（fee simple），若对其中之一的占有是基于某种附条件或可终止的利益，则不能产生占有混同。

双语例句：

It is generally believed that the unity of possession can arise from the contract of the parties. For example, the partnership property is jointly owned and managed by the partners. At this time, the unity of possession also occurs. Regarding the transfer of unity of possession, the legislation of various countries or regions generally stipulates that when separate possession is required, the joint owners shall make concerted efforts.

一般认为，占有混同可由于当事人的合同而产生，如对于合伙财产，由合伙人共同共有、共同管领，此时也产生共同占有。对于占有混同的移转，各国或地区的立法例一般规定，须移转单独占有时，各共同占有人应协力进行。

（2）Some of the unity of possession arising from the common relationship of the original right are based on the provisions of the law. For example, the joint inheritance is jointly owned and managed by the heirs before the division; some are based purely on the de facto management of the property. That is to say, there is no original joint relationship with the original right, and several people have the de facto control over the things and jointly occupy the things, such as several people infringe on the possessions of others or find the lost things.

由本权共同关系而产生的共同占有，有基于法律的规定而产生的，如共同继承遗产，在分割之前，由各继承人共同共有、共同管领；有单纯基于对物的事实上管领的，即原无本权共同关系，经数人共同对于其物有事实上管领力而共同占有其物，如数人侵夺他人的占有物或拾得遗失物。