1.NounA list of individuals or groups, usually for an organization of some kind such as military officers and enlisted personnel enrolled in a particular unit; a muster roll; a sports team, with the names of players who are eligible to be placed in the lineup for a particular game; or a list of students officially enrolled in a school or class.
"I'm number 12 on the roster for tonight's game."
2.NounA list of the jobs to be performed by members of an organization and often with the date and time that they are expected to perform them.
"The secretary has produced a new cleaning roster for the Church over the remainder of the year."
3.NounA schedule or timetable setting out shift times and dates for each employee of a business.
4.NounA bracketed list that shows the elements of a set.
5.VerbTo place the name of (a person) on a roster.
"I have rostered you for cleaning duties on the first Monday of each month."
6.VerbTo show the elements of a set by listing them inside brackets.