primordium; anlage; rudiment
Technical term in biology and embryology for the earliest stage of an organ or structure during development.
肢芽は四肢の原基である。
The limb bud is the primordium of the limbs.
Rare general use meaning the fundamental origin or basis of something. Mostly replaced by 根源 or 基礎 in modern Japanese.
This idea became the foundation of modern science.
leaf primordium
Compound of 原 (gen, 'original') and 基 (ki, 'base'). The biological sense is a direct translation of the German 'Anlage' or English 'primordium'.