Diet
The Diet, Congress, Parliament, Assembly
noun
The place you meet for deliberation in Japan is called the Diet. It's their version of congress.
ぎかい
This is a jukugo word that uses the on'yomi readings of the kanji. You should be able to read this on your own.
あいつら、何とかして議会の進行を妨害するつもりだぞ。
They are trying to obstruct the proceedings of Parliament by any means necessary.
正直、そのことについて議会で説明するのはかなり面倒です。
To be honest, it's extremely troublesome having to explain it at Congress.
もう議会で決定したことなんだ。
The Diet has already come to a decision.