The seriousness of his opening statement 'set the tone' for/of the meeting. [=his opening statement established that the meeting would be serious]
('Brit') I keep getting the 'engaged tone'. [=('US') 'busy signal'; the sound which indicates that the telephone line is already being used]
People will be more likely to listen to you if you 'tone down' your language a little.
(..) What is it with you two? - If there's something on your mind, say... - In my house? You left him in my house?! Lower your voice, or at least change your tone. Did you take care of it? Yes, that's what I do. Then thank you, and well done. Now let's get back to what's in front of us. (..)2017 TvShow: House of Cards Title: Chapter 65 Season: 5 Episode 13