listen in
verb
listened in; listening in; listens in
intransitive verb
1
: to tune in to or monitor a broadcast
2
: to listen to a conversation without participating in it
especially : eavesdrop
listener-in
ˌlis-nər-ˈin 
noun ˌli-sᵊn-ər-
Synonyms
- eavesdrop (on)
- overhear
See all Synonyms & Antonyms 
Example Sentences
Recent Examples on the Web Scientists are using underwater audio technology to listen in as whales talk to each other about things like ocean conditions and where to find the best krill to feed on. 
Fifth & Mission Podcast, San Francisco Chronicle, 1 Sep. 2022 But before that, Phoenix got to listen in on the singer's soundcheck and was greeted by his band and back-up dancers. Daniela Avila, PEOPLE.com, 18 July 2022 Scientists have used night-vision goggles to show that nocturnal bees can see in extreme darkness, clip-on microphones to eavesdrop on the vibrational songs of leafhoppers, and electrodes to listen in on the pulses of electric fish. Ed Yong, The Atlantic, 13 June 2022 After all, if a remote hacker could listen in to my typing and grab my passwords and other ‘secrets’ out of the ether, that would be quite the cause for concern. Davey Winder, Forbes, 8 June 2022 The translations are presented in video presentation formats, allowing users to read and listen in their respective native languages. Rufas Kamau, Forbes, 6 June 2022 Hear more by downloading the latest episode of Rhode Island Report, available on Apple Podcasts, Spotify, Amazon Music, iHeartRadio, Google Podcasts, and other podcasting platforms, or listen in the player above. Globe Staff, BostonGlobe.com, 28 July 2022 In the classical epoch, man’s speech and his thoughts were directed outward, to people who gathered to listen in the squares and the agoras. Merve Emre, The New Yorker, 25 July 2022 To ensure that guards could not listen in on their conversation, Rabbi Dresner told NPR, King tapped on the wall of his cell, signaling other jailed activists to begin singing. Emily Langer, Washington Post, 22 Jan. 2022 See More
Fifth & Mission Podcast, San Francisco Chronicle, 1 Sep. 2022 But before that, Phoenix got to listen in on the singer's soundcheck and was greeted by his band and back-up dancers. Daniela Avila, PEOPLE.com, 18 July 2022 Scientists have used night-vision goggles to show that nocturnal bees can see in extreme darkness, clip-on microphones to eavesdrop on the vibrational songs of leafhoppers, and electrodes to listen in on the pulses of electric fish. Ed Yong, The Atlantic, 13 June 2022 After all, if a remote hacker could listen in to my typing and grab my passwords and other ‘secrets’ out of the ether, that would be quite the cause for concern. Davey Winder, Forbes, 8 June 2022 The translations are presented in video presentation formats, allowing users to read and listen in their respective native languages. Rufas Kamau, Forbes, 6 June 2022 Hear more by downloading the latest episode of Rhode Island Report, available on Apple Podcasts, Spotify, Amazon Music, iHeartRadio, Google Podcasts, and other podcasting platforms, or listen in the player above. Globe Staff, BostonGlobe.com, 28 July 2022 In the classical epoch, man’s speech and his thoughts were directed outward, to people who gathered to listen in the squares and the agoras. Merve Emre, The New Yorker, 25 July 2022 To ensure that guards could not listen in on their conversation, Rabbi Dresner told NPR, King tapped on the wall of his cell, signaling other jailed activists to begin singing. Emily Langer, Washington Post, 22 Jan. 2022 See More Word History
First Known Use
1905, in the meaning defined at sense 1