and concurrently; in addition to; cum
Used to indicate that one person or thing serves two roles or functions simultaneously. Common in titles, job descriptions, and formal contexts.
This room serves as both a study and a bedroom.
He is the president and CEO.
This room is used as a study-cum-guest room.
He is both a teacher and a writer.
と is a plain listing particle that joins two separate items, whereas 兼 indicates that a single entity performs both functions simultaneously, as in 会議室兼倉庫 (meeting room cum storage room).
兼ねる is a verb meaning "to combine (roles)" and can stand alone as a predicate, while 兼 is the fixed conjunction placed between two nouns, as in 社長兼CEO.
combined use; multi-purpose; serving two purposes
concurrent post; additional role; serving also as
doing as a side business; running simultaneously · side business; second job
concurrent post; serving concurrently; holding an additional position · additional post; concurrent position
combine with; serve as both; hold an additional post; use with
combine both; have both qualities
uniting; unity; merging
studying two subjects together; double majoring; major-minor combination
additional post; concurrent post
From the kanji 兼, which originally means 'concurrently' or 'to combine'. The conjunction usage is a direct extension of this meaning.
operating simultaneously; running concurrently; concurrent operation
concurrent study of multiple schools or sects
concurrent post; holding multiple official posts
combined use; dual-purpose; serving two functions · holding two posts; concurrent positions
serving concurrently as; holding an additional post
serving concurrently as; holding the additional post of
having both; possessing both