phone

1 phone /ˈfoʊn/ noun
plural phones
1 phone
/ˈfoʊn/
noun
plural phones
Britannica Dictionary definition of PHONE
1 
: telephone : such as
a  [noncount] : a system that uses wires and radio signals to send people's voices over long distances
b  [count] : a device that is connected to a telephone system and that you use to listen or speak to someone who is somewhere else
— see pictures at office, telephone; see also cell phone, mobile phone, pay phone
2 
phones [plural] : headphones

on the phone

1 
: using a telephone to talk to someone
2 
British : connected to a telephone system
2 phone /ˈfoʊn/ verb
phones; phoned; phoning
2 phone
/ˈfoʊn/
verb
phones; phoned; phoning
Britannica Dictionary definition of PHONE
: to speak or try to speak to (someone) over a telephone system : telephone
[+ object]
— often + up in British English
[no object]
— often + up in British English

phone in

[phrasal verb]
1 
a  : to make a telephone call to a place (such as the place where you work)
b  : to make a telephone call to a radio or television program
— see also phone-in
2 
phone (something) in or phone in (something) : to deliver (something, such as a message) by making a telephone call