opera

As a noun operad

is (mathematics) a set of operations, each one having a fixed finite number of arguments and one output, which can be composed with others.

As a noun oper

is (internet) a network operator on irc.

As nouns the difference between opera and opers

is that opera is a theatrical work combining drama, music, song and sometimes dance while opers is plural of oper.

As a noun book is

book.

As a noun taxonomy

is the science or the technique used to make a classification.

As nouns the difference between opera and rock

is that opera is a theatrical work combining drama, music, song and sometimes dance while rock is the naturally occurring aggregate of solid mineral matter that constitutes a significant part of the earth's crust.

As a verb rock is

to move gently back and forth.

As a proper noun Rock is

{{surname|topographic|from=Middle English}} for someone living near a rock or an oak ( {{term|atter|lang=enm}} + {{term|oke|lang=enm}} ).

As an adjective semioperatic is

having some characteristics of opera.

As an adjective operalike is

resembling or characteristic of opera.