PL is an acronym for "Prooflike."
A PL coin features highly reflective surfaces that cast a clear reflection from a very short distance. This is in contrast to a DMPL ("Deep Mirror Prooflike") coin, which has considerably more reflectivity. Different experts and/or grading companies have different definitions of the exact number of inches of reflectivity required to justify a coin's designation as PL.
PL coins result from being struck by highly polished dies. The mirror-like quality resembles that of a proof coin, but a PL coin is not a proof coin. It is a business-strike coin intended for circulation and is therefore not proof but proof-like.
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