per recte et retro
/pəː ˈrɛkteɪ ˌɛt ˈrɛtrəʊ/Music. Now rare
adjective
Chiefly as a postpositive. Of a piece of music: containing a theme played both in the original form and in reverse; having the form of a canon cancrizans; written in this style.
adverb
Forwards and in reverse. Chiefly with reference to the movement of a canon cancrizans.
Origin
Early 19th century. From classical Latin per per + recte and retro.