Wheat
Barley
noun
The kanji and the word are exactly the same. That means they share meanings as well.
麦 refers to a group of European-style cereal grains, like wheat and barley but not rice and corn. To specify which 麦, you'll need to use compounds like 小麦 (wheat) or 大麦 (barley), though!
Since this word is made up of a single kanji that uses the kun'yomi reading which is the reading you learned with the kanji.
麦アレルギーです。
I'm allergic to wheat.
うちのハムスターは麦と米を気に入ったみたいです。
Our hamster seems to like wheat and rice.
大麦と小麦のちがいは何ですか。
What's the difference between barley and wheat?