There are different terms which are slightly different.

Perl5 has so called op-codes.

you can use B::Terse or B::Concise to see the opcode °

c:/tmp $ perl -MO=Terse -e'print "Hallo Discipulus"'

-e syntax OK
LISTOP (0x26eb410) leave [1] 
    OP (0x26eb3e0) enter 
    COP (0x26eb450) nextstate 
    LISTOP (0x26eb4e0) print 
        OP (0x26eb4b0) pushmark 
        SVOP (0x26eb520) const [1] PV (0x4c87b8) "Hallo Discipulus"
[download]

The difference seems that bytecode is kind of an artificial low level machine-code while op-code are more the tokens for high level commands.

see http://www.differencebetween.info/difference-between-opcode-and-bytecode

AFAIK it's even more complicated for Perl5 because some things are mangled.

From what I heard does Perl6 have even more possibilities. There is at least a Java-bytecode implementation (in the making ?)

HTH

°) and B::Deparse does nothing else than trying to back-engineer Op-code to most likely source code.