a fertilized egg is called a

A fertilized egg is called a zygote.

Quick Scoop

When a sperm cell successfully fuses with an egg cell (ovum), the very first single cell that forms is termed a zygote. This zygote is the starting point of a new organism’s development and contains a full set of chromosomes from both parents.

Key points

• A fertilized egg = zygote.

• “Embryo” is the next stage, used once that zygote starts dividing and developing further, especially after implantation in the uterus.

• The zygote stage is brief but crucial, marking the moment a new genetic individual first exists.

In simple terms: once the egg and sperm unite, you no longer call it just an egg—it becomes a zygote.

TL;DR: A fertilized egg is called a zygote.

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