next century
Refers to the century following the current one. Often used in speculative or futuristic contexts.
In the next century, space travel may become commonplace.
来月 means 'next month', while 来世紀 refers to the next century.
今世紀 means this century, whereas 来世紀 means the century that will come after it.
Compound of 来 (rai, 'next') and 世紀 (seiki, 'century').