noun
Business term referring to the customer's location or the customer as an entity, often used in contexts like 客先訪問 (customer visit) or 客先常駐 (on-site at the client).
明日は客先に直行します。
Tomorrow I'll go directly to the client's office.
客先の要望に合わせて仕様を変更した。
We changed the specifications to meet the client's requirements.
Compound of 客 (customer) and 先 (destination, place). The exact historical derivation is uncertain, but it is a straightforward business term.