cretaceous

What it means

1. not comparableOf or relating to chalk.
2. not comparableConsisting of chalk.

In a sentence

As with the Lejeuneaceae, this pattern of massive speciation appears to be correlated with the Cretaceous explosion of the angiosperms and the simultaneous creation of a host of new microenvironments, differing in humidity, light intensity, texture, etc.

1992, Rudolf M[athias] Schuster, The Hepaticae and Anthocerotae of North America: East of the Hundredth Meridian, volume V, Chicago, Ill.: Field Museum of Natural History, →ISBN, pages 3–4

Where it comes from

1. Latincreta
2. Latincretaceus“chalky”
3. Englishcretaceous

From Latin cretaceus (“chalky”), from Latin creta.