Verb
To cry out, e.g. when in pain.
(nautical) To call out; yell.
To start singing.
Source: en.wiktionary.org“‘Every time somebody asks you to sing out loud, you’re just going to do it.’ Source: Internet
I have to sing out of necessity but, you know, I guess my voice has been getting stronger and stronger from all this touring and making three records in the last six years. Source: Internet
The run maintained at a brisk 9-minute per mile pace and required soldiers to sing out with military cadence as they ran. Source: Internet