This is the 8348th most frequent Russian word.
младшая
The Russian word "младшая" means "younger" (feminine form).
The word 'младшая' is used here as an adjective describing the noun 'сестра', indicating that the sister is younger in age compared to the speaker or another sibling.
Моя младшая сестра учится в школе.
My younger sister studies at school.
The word 'младшей' functions as an adjective in this sentence, modifying the noun 'группе' to describe the younger group among several groups in a kindergarten.
Она работает в младшей группе детского сада.
She works in the younger group of the kindergarten.
Here, 'младшая' is metaphorically used as an adjective to describe a program version that is earlier or more initial compared to the newer versions.