benchmark

<performance> point of reference; qualitative or quantitative value against which performance is measured
See also: benchmarking <measurement>; performance characteristic; performance index; performance indicator
<surveying> point of accurately known elevation, identified by a mark or symbol set into concrete, stone, metal or other durable material and permanently fixed into the ground, to serve as a reference datum from which differences in elevation or level of other points can be measured
See also: temporary benchmark; permanent survey mark