noun, noun which may take the genitive case particle 'no'
earliest stage; very beginning; initial phase
Refers to the very first period or phase of something, often used in historical, developmental, or project contexts. Can function as a noun or modify another noun with の.
This technology is in its earliest stage.
In the very beginning, the plan was much smaller in scale.
Compound of 最初 (さいしょ, 'first, beginning') and 期 (き, 'period, stage'). The exact historical derivation is uncertain, but the combination naturally yields the meaning 'earliest stage'.