Classify vs Systematise - What's the difference?

As verbs the difference between classify and systematise

is that classify is to identify by or divide into classes; to categorize while systematise is an alternative spelling of systematize.

(en-verb)

to identify by or divide into classes; to categorize

to declare something a secret, especially a government secret

* See also

* (to declare a secret) declassify

* *

(systematis)