a continuous nonspatial whole or extent or succession in which no part or portion is distinct or distinguishable from adjacent parts
"The spectrum of human emotion exists as a continuum where feelings blend into one another without clear boundaries."
A continuous series or whole, no part of which is noticeably different from its adjacent parts, although the ends or extremes of it are very different from each other.
"The spectrum of political beliefs forms a continuum where neighboring ideologies share many views even though their positions at opposite ends differ radically."
In plain English: A continuum is an unbroken sequence of things that gradually change from one form to another without any clear breaks between them.
"The continuum between sleep and wakefulness is gradual, with no single moment marking the exact transition."
Usage: Use continuum to describe an unbroken sequence where gradual changes connect distinct endpoints. Avoid using this term for simple lists that have clear gaps between their items.
The word comes from the Latin continuum, which is the neuter form of continuus. It originally meant "that which contains or encloses" and entered English with this sense intact.