ground or grounds

Dear friends,
Can you tell me what is the difference between Ground And Grounds.Heaven and Heavens?

Thank you in advance

Hi Gerald

In the Longman English Dictionary ( the following definitions/example sentences for grounds / heavens are listed:

an area of land or sea that is used for a particular purpose:
fishing grounds

a good reason for doing, believing, or saying sth:
There are strong grounds for believing his statement.

small pieces of solid material that sink to the bottom of a liquid:
coffee grounds

the heavens
used in a literary context for “the sky”:
Just then the heavens opened (= it started to rain heavily).