ETYM Old Eng. apprentice, prentice, Old Fren. aprentis, nom. of aprentif, from apprendare to learn, Latin apprendere, equiv. to apprehendere, to take hold of (by the mind), to comprehend. Related to Apprehend, Prentice.
Works for an expert to learn a trade; SYN. learner, prentice.

To be or work as an apprentice.

In training.