21S

21s is a plural form derived from the numeral 21, used in contexts where numbers act as labels, identifiers, quantities, or timecodes. There is no single definition of "21s"; its meaning depends on the surrounding context.

In timekeeping and media, "21s" commonly denotes a duration of 21 seconds or a timestamp at the 21-second mark within a sequence. For example, a video editor might reference a clip beginning at 21s.

In catalogs, inventories, and data labeling, "21s" can function as a label or part of a code, such as entries labeled "21s-01" or file names like "clip_21s.mp4." In such uses, the trailing "s" helps distinguish variants or items associated with the base number 21.

In linguistic or typographic usage, "21s" can appear when listing multiple items that share the numeral 21, e.g., "the 21s in the dataset" to refer to all entries at the 21-unit category.

Overall, the term appears across domains because numbers are commonly used as identifiers and time indicators. When encountering "21s," readers should rely on the surrounding context to determine whether it denotes a quantity, a timecode, or a label.

See also: 21, seconds, timecode, numbering.