Crown-rump length (CRL) is a crucial measurement in the early stages of fetal development. It is often used to determine the age and growth of the fetus. However, CRL is not the only way to measure fetal development. There are several synonyms that can be used to refer to the same measurement. Some of the most commonly used synonyms include biparietal diameter (BPD), femur length (FL), and occipitofrontal diameter (OFD). These alternative measurements can be used to confirm CRL and provide additional information about the size and growth of the fetus. Using these synonyms helps to provide a full picture of fetal development.