tooriku, detaili, sõlme või masina pind, mida kasutatakse neile valitud koordinaadistikus soovitava asendi andmiseks – baseerimiseks (vt baseerimine)
a surface on a workpiece that establishes datum - a surface to which dimensions are referred on engineering drawings, and from which measurements are taken in machining or other engineering operations (see: basing)
