source of supply; channel; where to get something
Refers to the place, person, or route through which something is obtained. Often used in business, logistics, or when asking where to buy or acquire something.
Please tell me where to get this part.
It's important to secure a reliable source of supply.
出所 emphasizes the origin or provenance of something, often used for information or goods, whereas 入手先 focuses on the practical point of acquisition.
Compound of 入手 (にゅうしゅ, 'obtaining') and 先 (さき, 'destination' or 'source'). The combination straightforwardly means 'place/person from which one obtains something'.