sis

noun

1. A daughter of the same parents as another person; a female sibling.“My sister is always driving me crazy.”
2. A female member of a religious order; especially one devoted to more active service; (informally) a nun.“Michelle left behind her bank job and became a sister at the local convent.”
3. Any butterfly in the genus Adelpha, so named for the resemblance of the dark-colored wings to the black habit traditionally worn by nuns.
4. A senior or supervisory nurse, often in a hospital.