Some vocabulary you need to know for things to make sense:
Opera
Literal translation: from the Latin root “opus” for labor or work, the Italians used it to indicate an artistic work combining the visual (costumes, props, scenery, lighting) and the auditory (orchestra & voice). It highlights the multifaceted labor that goes into one great work. (See more under "What Is Opera?"
Composer
The person who writes the music for the opera. They work together with the librettist to create (compose) music that both moves the story along, and moves the audience with emotion.
Libretto/Librettist
From the Italian word for book, this person writes the words (lyrics) for the opera. They collaborate with the composer to make sure the story makes sense for the audience.
Aria
Italian for “air”, this is what the Italians called the songs in an opera when opera started over 400 years ago.
Two people=duet
Three people=trio
Four people=quartet
Five people=quintet
A group=tutti (It.), or ensemble (Fr.)
Supertitles
If you’ve ever seen a foreign film or cartoon in its original language, you’ve seen the written translation at the bottom of the screen. Those are subtitles. Sub from the Latin root "under" or "below". When you attend an opera, they are often displayed above the stage. They are then called supertitles. Super from the Latin root "over" or "above."