refers to the seeds of cereal crops, particularly those that are harvested for food.

can refer to any small, hard particle, especially in a technical context.

कण

English Usage: There was a grain of sand in my shoe.

Hindi Usage: मेरी जूती में एक कण रेत था।

an area of open land, especially one planted with crops or a specific type of vegetation.

a particular domain of study or activity.

क्षेत्र

English Usage: She is an expert in the field of environmental science.

Hindi Usage: वह पर्यावरण विज्ञान के क्षेत्र में विशेषज्ञ है।