Can not see the leaves properly...
Most likely this is a maple seedling.

Thanks tyrlych.
I have uploaded another picture. Hopefully this will show leaves properly. Since this has taken over the whole lawn do you know how to get rid of them ?

http://new.photos.yahoo.com/sanju_kolte/album/576460762400598394

Thanks.

I can't see the 2nd photo but I'd agree with the person who says it's a maple seedling.

A "weed" is any plant growing someplace we do not want it to grow. If this is a maple seedling and you do not want it growing there control is very simple, cut that seedling off at ground level and it will not keep on growing.

It's a Maple seedling. If they are in the lawn the first mowing will take care of it. You do not have to get on your hands and knees to pull them from your lawn.

Now..............if they are in your garden..........ya gotta get down on your hands and knees and pull. Get them early because the roots grow fast and you only want to have to pull once and not have the same one keep returning.