What is another word for by ear?
Pronunciation: [ba͡ɪ ˈi͡ə] (IPA) 
When it comes to describing the act of playing music without sheet music, the phrase "by ear" is commonly used. However, there are a number of synonyms that can be used to describe this skill. "Playing by ear" and "playing by feel" are both commonly heard phrases, as are "playing from memory" and "playing without score." Other possible synonyms include "improvising," "jamming," and "free-styling." While each of these terms has slightly different connotations, they all speak to the same underlying ability - the capacity to create music without relying on written notes or pre-planned compositions.
