An administrative domain exposes itself to other administrative domains through a type of logical element known as a border element.

管理域通过被称为边界元的一类逻辑单元使其自身展示在其他管理域的面前。

youdao

On sequence diagrams incoming and outgoing messages (A.K.A. interactions) for a sequence can be modeled by connecting the messages to the border of the frame element (as seen in Figure 2).

在序列图上一个序列接收和发送消息(又称交互)，能通过连接消息和框架元件边界，建立模型(如图2所见到)。

youdao

In addition to providing a visual border, the frame element also has an important functional use in diagrams depicting interactions, such as the sequence diagram.

除了提供一个图形化边框之外，用于图中的框架元件也有描述交互的重要的功能，例如序列图。

youdao

And it was during this period that the border tycoon displayed the another key element of Greek tragedy - hubris.

BBC: Sean Quinn's jailing reminiscent of Greek tragedy

But when Gordon talks about a Border Service, he's left out one rather key element - the police.

BBC: NEWS | UK | UK Politics | David Davis speech in full