An egg is a structure which the females of certain animal species lay as a means of reproduction.
Eggs used to satisfy the nutritional requirements of sentients are generally sourced from non-sentient tetrapods although eggs sources from nonsentient osteichthyes also see some use. The latter category has become rarer in common use, thanks to influence from the cetacean population.
Use of eggs from sentients of any variety to satisfy nutritional requirements is, of course, highly discouraged among all sentients who form social groupings.
Detailed analysis of such uses are outside the parameters of this document. Ask your mother.
Decorated eggs are known to have been used in pre-Excession historical celebrations, although the exact nature of these celebrations are unknown.
In modern times, eggs are featured during the Festival of Temporal Deviations as participants attempt to liquefy a chicken and reintroduce it to an eggshell which has been excavated for the purpose. Some superstitious persons have taken to pressing anachronistic metals into ovoids and calling them Murder Spider eggs, claiming they will ward off the creatures.