It is renting of the single portion of the real estate to several parties and each party is given a specific portion of the time during which it can use the portion of the real estate.
This is the concept which is also used in the computers where the operating system is used by several programs simultaneously.
Let there be a property for example a vacation house then it can be used by 3 parties a, b, c. a can use it in week 1, b can use it in the week 2 and c can use it in the week 3.
This concept is used in the mainframe and minicomputers. More than one user concurrently uses the computer which means they share the computer time.