
der Einkauf
shopping
The act of buying goods, usually food or other everyday necessities.
Ich muss nach der Arbeit noch den Einkauf für das Wochenende erledigen.
I still have to do the weekend shopping after work.
shopping / purchasing
Loading your saved state.

shopping
The act of buying goods, usually food or other everyday necessities.
Ich muss nach der Arbeit noch den Einkauf für das Wochenende erledigen.
I still have to do the weekend shopping after work.

shopping
All the goods that one has bought.
Hilfst du mir, den schweren Einkauf in die Wohnung zu tragen?
Can you help me carry the heavy shopping into the apartment?

purchasing
The department in a company responsible for procuring goods, raw materials, or services.
Unsere Abteilung für den Einkauf hat mit dem Lieferanten neue Konditionen ausgehandelt.
Our purchasing department negotiated new terms with the supplier.
The noun 'der Einkauf' (shopping/purchasing) is derived directly from the separable verb 'einkaufen' (to shop). It describes either the act of shopping or the result of it, meaning the goods bought.
Am Samstag gehe ich immer für die ganze Woche einkaufen.
On Saturdays I always go shopping for the whole week.
Whether the action (meaning 1) or the purchased goods (meaning 2) is meant can often be recognized from the verb. Verbs like 'erledigen' (to take care of) or 'machen' (to do/make) refer to the action, while verbs like 'tragen' (to carry) or 'auspacken' (to unpack) refer to the goods.
Ich muss noch schnell den Einkauf machen.
I still have to quickly do the shopping.
When referring to the activity of shopping, the noun is often used with the verbs 'machen' (to do/make) or 'erledigen' (to take care of). The phrase 'zum Einkauf gehen' (to go shopping) is also very common.
Wir müssen am Wochenende einen großen Einkauf machen.
We have to do a big shopping trip on the weekend.
In a professional context, 'der Einkauf' (purchasing) refers to the department of a company that is responsible for procuring materials. People then often say 'im Einkauf arbeiten' (to work in purchasing).
Er arbeitet seit fünf Jahren im Einkauf unserer Firma.
He has worked in purchasing at our company for five years.
purchase
Kauf generally refers to a single purchase made in exchange for payment. Einkauf usually means getting groceries or other everyday goods, often as one shopping trip or process. Kauf therefore fits a single item, while Einkauf is more suitable for getting several needed goods.

Der Einkauf für das Abendessen war gut geplant.
The shopping for dinner was well planned.
Der Kauf des neuen Mixers war gut geplant.
The purchase of the new blender was well planned.