What's the correct term for the lambda vs proc or Struct vs Class distinction?

What's the correct term for the lambda vs proc or Struct vs Class
distinction?

References

Reference NO 1

http://stackoverflow.com/questions/15202639/whats-the-correct-term-for-the-lambda-vs-proc-or-struct-vs-class-distinction

Reference NO 2

http://en.wikipedia.org/wiki/Closure_(computer_science)

Reference NO 3

http://en.wikipedia.org/wiki/First-class_function

Reference NO 4

http://www.ats.ucla.edu/stat/sas/seminars/sas_repeatedmeasures/

Reference NO 5

http://www.rubymotion.com/developer-center/guides/runtime/

Reference NO 6

http://www.ruby-doc.org/docs/ProgrammingRuby/

Reference NO 7

#EANF#

Reference NO 8

#EANF#