So why “No. 2”?

The hardness of writing pencils, which is related to the proportion of clay (used as a binder) to graphite in the lead, is designated by numbers from 1, the softest, to 4, the hardest.

Is it me, or do others also recall its Big Bang Theory reference?

That’s all well and good, Dictionary Twitter Account, but how do I remember this?

‘Homo’ is Greek for “one and the same; similar; alike.”

Homonym
Homo (same) + Onyma (name)

Homophone
Homo (same) + Phōnos (sounding)

Homograph
Homo (same) + Graphein (to write)