pronucleus

Either of the two haploid nuclei (of a sperm and ovum) that fuse during fertilization

Japanese Meaning

受精時に、精子と卵からそれぞれ生じる半数性核のうちの一方

Under the microscope, the embryologist observed the male pronucleus drifting toward the female pronucleus before fusion.

顕微鏡の下で、胚学者は精子由来の前核が卵子由来の前核に向かって移動し、受精時に融合するのを観察した。

Sense（1）

Either of the two haploid nuclei (of a sperm and ovum) that fuse during fertilization

pronuclei

（ plural ）