Definition of blister. 1  1 : a fluid-filled elevation of the epidermis â compare water blister. 2  2 : an enclosed raised spot (as in paint) resembling a blister. 3  3 : an agent (such as lewisite) that causes blistering. 4  4 : a fungal disease of plants marked by raised patches on the leaves.
One acre equals 0.0015625 square miles, 4,840 square yards, 43,560 square feet or about 4,047 square metres (0.405 hectares) (see below). While all modern variants of the acre contain 4,840 square yards, there are alternative definitions of a yard, so the exact size of an acre depends on which yard it is based.
Now that we know a bit about acres and square feet, we can move to conversion of these units and find out how many square feet there are in an acre. One US customary acre is equivalent to 43 560 square feet, 4840 square yards, or about 4047 square meters.ow that we know a bit about acres and square feet, we can move to conversion of these units and find out how many square feet there are in an acre. One US customary acre is equivalent to 43 560 square feet, 4840 square yards, or about 4047 square meters.