Learner's definition of LONG–TERM
: lasting for, relating to, or involving a long period of time
The long-term effects of the medication are not known.
The company has a long-term plan/strategy for success.
His long-term memory is still okay, but his short-term memory is failing. [=he is still able to remember things that happened long ago but it is difficult for him to remember things that happened recently]
long-term care for the elderly
a long-term investment