der Anruf
call
The act of establishing a connection with someone by telephone in order to speak with them.
Ich erwarte einen wichtigen Anruf aus dem Büro.
I'm expecting an important call from the office.

call
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call
The act of establishing a connection with someone by telephone in order to speak with them.
Ich erwarte einen wichtigen Anruf aus dem Büro.
I'm expecting an important call from the office.

The noun 'der Anruf' (call) is derived directly from the separable verb 'anrufen' (to call). It describes the act of calling as a noun.
Ich muss später noch einen Anruf erledigen.
I still have to make a call later.
'Anruf' (call) is often combined with certain verbs. You can 'bekommen' (get), 'erhalten' (receive), or 'entgegennehmen' (take) a call, or 'tätigen' (place) and 'machen' (make) one yourself.
Der Chef hat heute Morgen schon drei Anrufe für Sie entgegengenommen.
The boss has already taken three calls for you this morning.
Common adjectives that describe a call are 'wichtig' (important), 'dringend' (urgent), 'kurz' (short/brief), 'persönlich' (personal), or also 'verpasst' (missed), if you couldn't answer it.
Ich habe einen verpassten Anruf von einer unbekannten Nummer.
I have a missed call from an unknown number.
telephone
'das Telefon' and 'der Anruf' are both connected to using the phone, but they do not mean the same thing. 'das Telefon' is the device you use to speak or answer a call. 'der Anruf' is the action or attempt to reach someone by phone. The words can be confused because in both cases you are talking about the same kind of situation. But you buy or repair a telephone, while you receive, make, or miss a call. Remember: the telephone is the device; the call is the event.

Am Montag warte ich auf einen wichtigen Anruf von meinem Chef.
On Monday, I am waiting for an important call from my boss.
Vor dem Wochenende ist das Telefon in der Werkstatt kaputtgegangen.
Before the weekend, the telephone in the workshop broke.