Accel should be correctly written as "Accel" followed by punctuation marks. Its full name is accelerando, which means "faster and faster" in music terminology, meaning that the speed of music performance is getting faster and faster. Accelerando is a musical term, which includes not only the elements of music, such as speed, expressiveness, dynamics, mode, harmony and melody, but also the periods and genres of music (such as medieval period, baroque period, classical period, The Romantic Period, national music genre and so on). ).

Mastering the internal relaxation of speed contained in speed terms is very beneficial to the performance of music, especially the cohesion of phrases and the performance at the end of paragraphs. Related terms: Ritardando: slow down gradually, MenoMosso: slow down, Stretto: speed up temporarily, Rubato: elastic speed play, etc. It is worth noting that many temporary speed changes are varied and nuanced, such as Rallentando and Ritardando, which all mean to slow down.