also: スピーカーホン · スピーカフォン
speakerphone
A telephone with a built-in speaker and microphone, allowing hands-free conversation. Common in offices and conference calls.
During the meeting, we used the speakerphone so everyone could hear the conversation.
Please switch to speakerphone so you can free up your hands.
Shortened variant without the long vowel mark; rarely used.
Borrowed from English 'speakerphone'.