This is the 4962nd most frequent Japanese word.
穀
"穀" means "grain" or "cereal."
In this sentence, '穀物' refers to grains or cereals as a category of foods.
穀物は健康に良い食品です。
Grains are healthy foods.
Here, '穀倉' refers to a granary or storage place for grains.
日本では、古くから穀倉として利用されてきた建物があります。
In Japan, there are buildings that have historically been used as granaries.
The term '穀類' in this context refers to different types of grain crops.