Early 17th century; earliest use found in Thomas Bilson (?1547–1616), bishop of Winchester. From inform + -ance. Compare post-classical Latin informantia reception of form or formal cause.
informance2
/ɪnˈfɔːməns/
noun
A performance intended to be both educational and entertaining; especially a musical concert which includes an informative talk about the piece or instruments being played.
Origin
1970s; earliest use found in The Chicago Tribune. Blend of either informative or information and performance.