Definitions for "Concurrent sentence"
Where a person is sentenced to imprisonment for two or more offences, the sentences may be ordered to be served concurrently ie: at the same time rather than one after the other.• Sentencing Options
A sentence that is one of two or more sentences imposed at the same time after conviction for more than one offence and to be served at the same time, or a new sentence imposed upon a person already under sentence(s) for a previous offence(s), to be served at the same time as one or more of the previous sentences.
Sentences for more than one crime which are to be served at one time. When a criminal defendant is convicted of two or more crimes, a judge sentences him/her to a certain period of time for each crime. Then out of compassion, leniency, plea bargaining or the fact the the several crimes are interrelated, the judge will rule that the sentences may all be served at the same time, with the longest period controlling.(http://dictionary.law.com)