million; one million
A katakana way to say or evoke 'one million.' In ordinary counting, 百万 is often the more standard Japanese expression, while ミリオン is common in compounds and promotional wording such as ミリオン再生 or ミリオンヒット.
That video passed one million views overnight.
They released a new song aiming for a million-hit success.
million-seller
Abbreviation of ミリオンセラー. Used mainly in entertainment, publishing, and sales contexts to mean that a work has sold a million copies or units.
See also: ミリオンセラー
Their debut album became a million-seller.
The novel became a million-seller within half a year of its release.
This album has finally surpassed one million in sales.
The video racked up three million views.
The debut single instantly became a million-selling hit.