This is the 8116th most frequent French word.
triplett
"Triplett" is not a French word. You may mean "triplet," which refers to three identical items or siblings born at the same time.
In this sentence, 'triplettes' refers to three siblings born from the same pregnancy (triplets).
Elle est fière d'avoir des triplettes dans sa classe.
She is proud to have triplets in her class.
Here, 'triplettes' is used colloquially to refer to groups of three individuals working together.
Il a fallu des triplettes pour décorer cette grande salle.
It took trios to decorate this large hall.
In this instance, 'triplettes' refers to sets of three gears used within a mechanical system.