Mole Day is celebrated among chemists on October 23, between 6:02 a.m. and 6:02 p.m. The time and date are derived from Avogadro's number, which is 6.02 × 1023, defining the number of molecules in a mole, a basic chemistry unit.
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dB is the abbreviation for Decibel; see Bel
DB is a French automobile maker; see DB (car)
DB is the abbreviation for Deutsche Bahn, ...