bridesmaid
n.a woman or girl who helps the bride during a wedding. You usually choose your close friends or sisters for this role.
n.a female attendant who assists the bride during a wedding ceremony. Often used metaphorically in the phrase 'always a bridesmaid, never a bride' to describe someone who never achieves top success.
“My sister asked me to be her bridesmaid next summer.”
“The bridesmaids wore matching silk dresses and carried small bouquets as they walked down the aisle.”
“While the maid of honour handles most of the logistical planning, each bridesmaid is expected to provide emotional support and assist with the ceremony's choreography.”
Commonly used in the plural when referring to the entire group of attendants.
From bride + -s- + maid. In the sports and entertainment sense: in reference to the saying always a bridesmaid, never a bride.
Etymology adapted from Wiktionary, available under CC BY-SA 4.0.