The syllable 'op-' may be the stem for Ops, the wife of Saturn in ancient, classical Roman mythology. Or it may be the prefix to Latin nouns and verbs. The form 'op-' is the form of the prefix when it's added to the beginning of nouns and verbs that begin with the letter 'p'. The form 'ob-' is used in front of all other letters. The word 'ob' also is a preposition of the same meaning: 'because of', 'before', 'in front of', 'in return for', on account of', 'to the purpose', or 'towards'.
the word "work" in latin is opus
The Latin word opus translated into English mean deed or labor.
Opus.
domus opus
opus
Opus Christi.
Magnum Opus.
A musical work.
operation, optional
This is not how to ask a question. There are two words in this phrase, not one. Magnum Opus is Latin, for Great Fruit, referring to the fruits of labour, so-called, of research or other concentrated effort in the Arts
The usual expression is simply "Opus est" (It / that is needed), as pronouns such as "id" (it) are usually omitted in Latin, because they are redundant with the tense of the verb.
There isn't a specific word for 'firework' in Latin, but if you divide it into 'fire' and 'work' you'll get 'ignis opus'.