Pronounced bo (falling tone), same as "bei". "Shuowen Jiezi" explains it as a two-year-old ox. The character has the "ox" radical and "shi" as the phonetic component.
Additionally, "Yupian" records it as referring to a long-bodied ox.
Note: According to "Erya · Shixu," a long-bodied ox is called "mo." The commentary states: referring to a long-bodied ox. The explanation clarifies: all long-bodied oxen are called "mo," and are written with the character "mo." "Diao" and "mo" are different ancient and modern forms of writing.
Furthermore, "Jiyun" records another explanation: one explanation says an ox with long and large legs is called "diao." Sometimes it is also written as "lao."