a person who likes to join groups
"After moving to the new city, she quickly became a joiner by signing up for three local running clubs within her first week."
a woodworker whose work involves making things by joining pieces of wood
"He was hired as a joiner to build the custom bookshelves from scratch, carefully fitting every piece of timber together."
A maker of wooden furniture or fittings.
"The editor installed a joiner to seamlessly merge the two audio tracks without any gaps."
A thing that joins two separate items, e.g. software to connect video or music clips.
A surname.
"The new neighbor, Mr. Joiner, waved at me from his porch as I walked by."