You have to know what you want before you can get what you want and the proper vocabulary will help achieve that!
BY: Is referring to the sire/stallion ONLY (example: My filly is “BY” RL Best Of Sudden).
OUT OF: Is referring to the dam/mare/mother of an offspring of any age (example: My filly is “OUT OF” Hot Little Mama).
MAIDEN MARE: Is referring to a mare (any age) that has not produced a foal but can be in foal.
HALF BROTHER/SISTER: Is referring to a horse that is “Out Of” the same mare/dam/mother, Does Not refer to the sire/stallion in any manner.
BROODMARE SOUND ONLY: Is referring to the fact the mare is Not sound to ride, for whatever minor to major reason but IS sound to reproduce.