There was a time when my interest in chemistry and such was quite a bit beyond that state in which it exists presently. During this time I read various threads concerning concepts and happenings and one of them is Mole Day.
Mole day is observed each year on October 23 from 6:02 am to 6:02 pm commemorating Avogadro's Number, 6.02 x 1023 ... a basic chemistry unit of measurement taught to me by Mrs Eadie F Cooper at Wagener-Salley High School round about 1971 or so.
Nowadays I could really give a rip as my technical interests surround machines and languages ... but back then I considered such things of paramount importance. I believe the various activities in which I participated with the various chemistry geeks were a part of the decline in that importance I felt for the entire shebang.
So when it comes to molecules, one mole is a mass in grams whose number is equal to the molar mass of the molecule aka "gram molecular weight". One mole of any substances contains Avogadro's Number of molecules or atoms of that particular substance as discovered by one Amadeo Avogadro who became known for this measurement posthumously.