A decasecond represents ten seconds in the International System of Units. While technically valid as an SI multiple, it is rarely used in practical engineering or scientific work. Most professionals prefer to measure short durations in standard seconds or switch directly to minutes for longer intervals.
Heard on the job
The reaction sequence completes in about three decaseconds, but we just log it as thirty seconds.
Insider tip
You will almost never see this unit used in technical documentation, as standard practice dictates using plain seconds up to at least sixty.