Avogadro

4 clues
---'s number
He's known for a number
You might get his number in chemistry class
Italian scientist who lent his name to a number
Similar answers:
Adrockinghorse
Adroit
Adroite
Adroiter
Adroithintwit
Adroitly
Adroitness
Adroopinthebucket
Adrop
Adropinsnails
Adropintheocean
Adroveofmartinets
Amedeoavogadro
Avogadro
Avogadrosnumber
Badromance
Breadroll
Dadrock
Eastoffroadroom
Gadroon