This is a teacher standing in front of their blackboard. The board has a shelf on it to hold chalk or dry erase markers. The teacher has his/her mouth open wide and is teaching students how to sing. He/she has musical notes coming out of his/her open mouth.
This is a Singing icon. We've made it in iOS style
, first introduced in iOS version 7 and supported in all later releases up until now (at least iOS 11). This style is based on thin two-pixel lines and is optimized for 50x50 px. Unlike other vector icon packs that have merely hundreds of icons, this icon pack contains 13,100 icons, all in the same style and quality.