Technical term used mainly in veterinary or biological contexts to describe the ability to conceive or reproduce, especially in animals.
This research investigates methods to improve fertility in cattle.
We analyzed factors affecting fertility in pigs.
Compound of 妊 (にん, 'pregnancy') and 性 (せい, 'nature, quality'), literally 'pregnancy nature'. The exact historical derivation is uncertain, but the term is used in modern technical contexts.