> Individual pulses of cold climate within an ice age are termed glacial periods (glacials, glaciations, glacial stages, stadials, stades, or colloquially, ice ages), and intermittent warm periods within an ice age are called interglacials or interstadials.
You can actually see the definition (albeit a little verbose) as the first sentence of that article:
> An ice age is a long period of reduction in the temperature of Earth's surface and atmosphere, resulting in the presence or expansion of continental and polar ice sheets and alpine glaciers.
On a technicality, you can get me for not mentioning the snow capped mountains part, I'd concede on that. That part is actually news to me. All the same, the earth is colder than it usually is. [1]
An interesting thing I like to bounce around in my head: Could we live in the interior of the Pangean super continent if we had to? Interesting stepping stone between Earth's current, very mild climate, and trying to live in a place like Venus. Definitely would have to live like mole people.