Which term would indicate to play somewhat slower than ordinary speed?

The term that indicates to play somewhat slower than ordinary speed is "Adagissimo." This term suggests an even slower tempo that is often associated with a very relaxed, flowing style of music. While "Lento" and "Adagio" are terms that also denote slower speeds, "Adagissimo" is understood to convey a tempo that is significantly slower, emphasizing a marked difference from the usual pace. In contrast, "Allegretto" and "Moderato" imply faster or moderate speeds, making them unsuitable options for indicating a slower tempo.

Understanding these distinctions helps musicians interpret the intended expression and emotion behind a piece of music when encountering these tempo markings.