Involving three sides — three countries, three companies, three groups sitting at the same table. A trilateral meeting is one where all three are there together, each speaking for itself. That is the whole point of the word: not three separate conversations, but one conversation with three sides in it.

Involving three sides牽涉到三方—— three countries, three companies, three groups sitting at the same table三個國家、三家公司、三個團體坐在同一張桌子上。 A trilateral meeting is onetrilateral meeting（三邊會議）指的是 where all three are there together三方都到場、 each speaking for itself各自代表自己發言的會議。 That is the whole point of the word這正是這個字的重點： not three separate conversations不是三場各自獨立的對話， but one conversation with three sides in it而是一場對話裡有三方。

It lives almost entirely in news and government language — trilateral talks, a trilateral agreement, trilateral cooperation. You will meet it constantly in reporting about Taiwan, Japan, the US, Korea and China, because so much diplomacy happens in threes.

It lives almost entirely in news and government language它幾乎只出現在新聞和政府用語裡—— trilateral talkstrilateral talks（三邊會談）、 a trilateral agreementa trilateral agreement（三邊協議）、 trilateral cooperationtrilateral cooperation（三邊合作）。 You will meet it constantly in reporting about Taiwan, Japan, the US, Korea and China你會在關於台灣、日本、美國、韓國和中國的報導裡經常遇到它， because so much diplomacy happens in threes因為很多外交場合都是三方進行的。

Compare bilateral (two sides), which is far more common, and multilateral (many sides). Journalists sometimes shorten the pattern into a name: the Trilateral Commission is a real organisation, so a capital T can mean that specific group rather than the plain adjective.

Compare bilateral (two sides)可以拿bilateral（雙邊，兩方）來比較， which is far more common它更常見； and multilateral (many sides)還有multilateral（多邊，多方）。 Journalists sometimes shorten the pattern into a name記者有時候會把這個說法縮成一個專有名稱： the Trilateral Commission is a real organisationTrilateral Commission（三邊委員會）是真實存在的組織， so a capital T can mean that specific group rather than the plain adjective所以開頭大寫的T可能是指這個特定團體，而不是單純的形容詞。

In geometry it can simply mean 'having three sides', but that use is rare — for shapes people say triangular. It is formal. In ordinary speech you would just say 'a meeting between the three countries'.

In geometry it can simply mean 'having three sides'在幾何學裡，它可以單純指「有三條邊」， but that use is rare但這種用法很少見—— for shapes people say triangular講形狀時人們會說triangular。 It is formal這是個正式的詞。 In ordinary speech you would just say平常講話你只會說 'a meeting between the three countries'「a meeting between the three countries（三國之間的會議）」。