The ASL sign "sister" in American Sign Language has a few variants of the origin.
Meaning: a girl or woman who has the same parents as another person; female sibling.
Pronunciation (sign description): There is a few variants of the ASL sign "sister".
Variant 1: Thumb of dominant "10" hand is in contact with cheek while non-dominant horizontal forefinger is held space, with index finger pointing out, palm down. Dominant hand moves towards, transforming the "10" handshape into the "1" handshape where both forefingers meet at the edges of fingers, both palms down.
Variant 2: Thumb of dominant "L" handshape (also variant of "10" handshape) is in contact with cheek moves toward non-dominant horizontal forefinger, where bottom of dominant hand rests on top of non-dominant hand.
Etymology: This sign originally was derived from the compound GIRL+SAME. Apparently, it evolved into a few variants through the process of assimilation as all languages do. Thus, the variant 1 is believed to be older and the variant 2 is the modern version.
Related signs: SIBLING, FAMILY.
Meaning: a close female friend or companion.
Sign description glossed as: QUOTATION-MARK(2h) + SISTER.
Related signs: FRIEND, COMRADE.
Meaning: a associate or member of a labor union or other organization such as sorority.
Related signs: MEMBER, SORORITY.
Meaning: a member of a religious order or congregation of women. See NUN.
sisterly: having the characteristics of a sister or sisters; behaving or feeling like a sister.
Sign description in ASL glossed as: SISTER+LIKE.
First 100 words.
As you feel more comfortable with the first few hundreds of ASL signs, progress further with your vocabulary and learn signing more.