regular customers; built-in audience
Refers to a stable base of repeat customers or a loyal audience, often in business or entertainment contexts.
あの店は固定客が多いので、いつも賑わっている。
That shop is always busy because it has many regular customers.
This theater company has a built-in audience.
Compound of 固定 (こてい, 'fixed') and 客 (きゃく, 'customer').