The meaning of the rule of thumb means to apply a procedure
that is easily learned and can be use d at once. It is not accurate or exact when determining
a value or figuring things out. The
phrase is taken from carpenters who use their thumb rather than a ruler to
measure things. Others say that it
refers to planting using your thumb to plant seeds in the field. Either way it’s all about estimating something
that is not that accurate.