vols
n. countable B2 Upper Intermediate vols
n. a short way of writing 'volumes'. You see this in libraries or lists of books to show how many books are in a set.
n. the standard abbreviation for the plural form of 'volume'. Typically used in bibliographic citations or library catalogues to indicate a multi-part work.
The encyclopedia set has 20 vols.
The bibliography lists the complete works of the author as a collection spanning twelve vols.
In the rare books section, the archivist noted that several vols were missing from the original eighteenth-century set, likely due to a fire in the previous century.
Usage
Always plural in this form; the singular abbreviation is 'vol.' with a period.