"In ovo" refers to a process or event that occurs before hatching. Synonyms for this term might include "in embryonic development," "during gestation," or "during incubation." These phrases all describe processes that occur within the egg before it hatches. Other related terms might include "pre-hatching," "pre-natal," or "pre-birth." Each of these terms describes a different aspect of the developmental process leading up to hatching, but all are closely related to the concept of "in ovo" and can be used interchangeably in many contexts. Whether discussing the growth and development of birds, reptiles, or other animals, these synonyms can help to provide clarity and precision in scientific discussions.