ground

• soil; earth; bottom; field, area; base, foundation
set on the ground; found, establish; teach someone the basics; attach to the earth (about an electrical conductor)
on or near the ground; broken into fine particles; shaped by grinding
the ground is the surface of the earth.
ground is land.
a ground is an area of land which is used for a particular purpose.
the grounds of a building are the land which surrounds it and belongs with it.
a ground is an electrical wire which allows current to pass from an appliance into the ground. it makes the appliance safe even when there is something wrong with it; used in american english.
you can also use ground to refer to a subject or range of things when you are considering it as an area to be covered or dealt with.
something that is grounds for something else is a reason or justification for it.
if you gain ground, you make progress or get an advantage. if you lose ground, you find yourself at a disadvantage.
you also use ground to refer to a place or situation in which particular ideas, attitudes, or organizations can develop and be successful.
ground is also used to describe people or things that operate or are found on the surface of the earth, rather than in the air.
if aircraft or pilots are grounded, they are not allowed to fly.
if an argument or opinion is grounded in or on something, it is based on that thing.
ground is also the past tense and past participle of grind.
see also grounding.
on grounds of, on the grounds of, and on the grounds that introduce the reason for a particular action.
when you talk about what is happening on the ground, you are talking about what is really happening in a situation, rather than what the people who are in control are saying or thinking about it.
if you go to ground, you hide somewhere for a period of time.
if you run something to ground, you find it after a long, difficult search.
if you break fresh ground or break new ground, you make a discovery or start a new activity.
if you get something off the ground, you get it started.
if you stand your ground or hold your ground when people are opposing you, you do not retreat or do not accept something that you do not want to accept.
if you give ground when people are opposing you, you retreat or accept something that you do not want to accept.