A proton. A proton has a mass of 1 a.m.u. while an electron has a mass of 1/1840 a.m.u.

A magnitude is factor of 10

An order of magnitude is a factor of "about 10". Two orders of magnitude is about 100.

For example, if something is two orders of magnitude higher than 3, it would be about 300. Order in this case means about, or approximate.

To the nearest order of magnitude , 3200 is 3000

By orders of magnitude, yes.

No - many orders of magnitude SMALLER

Yes, by several orders of magnitude.