Tray
Ancestral Festival
noun
The kanji 盆 means tray or ancestral festival. The お just adds politeness or respect. So お盆 also means tray, or refers to the ancestral festival also known as Obon.
Usually, the context will tell you which meaning for お盆 is being used, but you can also distinguish between them by the pitch accent. お盆 for "tray" uses a Low-High-High accent (like our female audio), and お盆 for "ancestral festival" uses a Low-High-Low accent (like our male audio).
This is a jukugo word that uses the on'yomi readings of the kanji. You should be able to read this on your own.
今日の宿題は、英語で「お盆」の説明を考えてくる事です。
Today’s homework is to make an explanation of what Obon is in English.