A zygote was the earliest, unicellular stage of an organism's development.
In the late 32nd century, the Doctor had developed the habit of referring to his cadets at Starfleet Academy as "little zygotes." (SA: "Kids These Days", "Vox In Excelso")
Chancellor Nahla Ake later used this same phrase to describe the cadets in 3196, following her mission to Kasq alongside the Doctor and SAM. (SA: "The Life of the Stars")