A means by which an RFID reader identifies a tag with a specific serial number from a number of tags in its field.

There are different methods of singulation, but the most common is "tree walking", which involves asking all tags with a serial number that starts with either a "1" or "0" to respond.

If more than one responds, the reader might ask for all tags with a serial number that starts with "01" to respond, and then "010". It keeps doing this until it finds the tag it is looking for.