A Part
A Role
noun
One wing is just a part of the bird or plane it's attached to. But that one wing plays a role that's very important!
This word usually comes up in the phrase 〜の一翼を担う (to play a part in…).
This is a jukugo word that uses the on'yomi readings of the kanji. You should be able to read this on your own.
大きなプロジェクトの一翼を担えることになりました。
I have been entrusted to take on part of the large project.