Seldom is an adverb. Just like 'rarely' is used to describe how often something occurs, 'seldom' is used in that same context to qualify how often something is done or happens.
Often, means frequently, or many times/ seldom, means rarely or not many times. Often and seldom are antonyms.
Black is to white as seldom is to often.
The word often is an antonym (opposite) of seldom, and has a silent 't'.
White is to black as seldom is to often.
Often
White is to black as seldom is to OFTEN (or FREQUENTLY).
Not often.
it means not very often
Not often; rarely
Seldom!
Often