= Entanglement area law
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An entanglement area law bounds a region's <entanglement entropy> by its boundary size rather than its volume, in a specified family of states and with a stated short-distance convention. For a lattice region $A$, a typical form is $S(A)\leq c|\partial A|$ with a constant independent of the region's linear size.
The physical intuition is that correlations contributing most strongly across the cut can be concentrated near its boundary. A generic highly entangled state need not satisfy this: independent Bell pairs joining many interior sites to the exterior can produce volume-scaling entropy. <Tensor-network area-law bounds> make the boundary counting explicit through the number of cut bonds. Area laws are therefore useful structural constraints, not automatic consequences of calling a state quantum or a Hamiltonian local.
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