Call number set up, like a momentous step taken in 1969?
I believe the answer is:
one-man
'a momentous step taken in 1969?' is the definition.
I can't tell whether this definition defines the answer.
'call number set up' is the wordplay.
'call' becomes 'name' ('name' can be a synonym of 'call').
'number' becomes 'no' (abbreviation for 'number').
'set up' says the letters should be written backwards.
'name'+'no'='nameno'
'nameno' back-to-front is 'ONE-MAN'.
'like' acts as a link.
Can you help me to learn more?
(Another definition for one-man that I've seen is " (Of show) performed by a single person".)