preconceived notion; stereotype; ready-made idea
Refers to fixed, unquestioned ideas or stereotypes one holds, often without direct experience. Common in critical or analytical contexts.
Let's value new ideas without being bound by preconceived notions.
His opinion is just based on stereotypes.
固定観念 is a fixed idea or obsession, often more personal and rigid; 既成観念 emphasizes socially or culturally ready-made notions.
先入観 is a preconception or prejudice formed before knowing the facts; 既成観念 is a broader set of established ideas or stereotypes.
Compound of 既成 (kisei, 'already formed, established') and 観念 (kannen, 'idea, notion'). The exact historical derivation is uncertain, but the term is a modern Sino-Japanese coinage.