Zspread Vs. Nominal Spread completely, adjusted, getting, understand, everyone

vagabond

Hi everyone,
I'm getting those two confused. I completely understand the Option adjusted spread but I keep confusing the Zero volatiliy spread and the nominal spread.
Any pointers?

Thx

dotamasta

the z spread is the constant spread off of any point on the spot rate curve

the nominal spread is the spread off any ONE point on the treasury yield curve