A 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.
"The coach reviewed the final roster to ensure only eligible players were listed before the championship game."
In plain English: A roster is an official list of people who are part of a team, class, or group and whose names need to be kept track of.
"The teacher posted our class roster on the whiteboard for everyone to see."
Usage: Use "roster" to refer specifically to an official list of members within an organized group like a sports team or company staff, rather than just any general inventory. You can also use it as a verb when describing the act of adding someone's name to that specific membership list.
To place the name of (a person) on a roster.
"The manager decided to roster the new intern for the summer shift."
In plain English: To roster means to put someone's name on an official list of people scheduled for work or duty.
"The coach will roster all the players on Friday for next week's games."
Borrowed from Dutch rooster ("gridiron, table, list"), from Middle Dutch roosten ("to roast"). More at roast.