Simple Definition of in-service

from our Learner's Dictionary

in-service

adjective

always used before a noun
: happening while you are being paid to work
a day of in-service training for teachers

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“In-service.” Merriam-Webster.com Simple Definition, Merriam-Webster, https://www.merriam-webster.com/simple/in-service. Accessed 24 Jun. 2026.

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